Android实现文本排版
时间：2021-02-16 10:43:33|栏目：Android代码|点击： 次
在项目中有一个小功能需要实现，就是对多行文本进行排版布局，每一行的内容又分为两部分，左边为标题，右边为描述，左边内容长度不确定，右边的内容需要对齐，如有换行也需要对齐右边的文本。
一、效果图
可以看到内容分成了两部分，左边的颜色与右边不一致，右边的描述文案统一对齐。
二、实现方案
以上功能，由于输入内容输入行数不确定，并且左边的文案长度也不确定，因此不能直接在布局中实现，基于此这里主要实现了以下6种方式
方案1
采用自定义控件的方式，继承TextView，重新onDraw函数，实现如下：
/**
* 计算出左边最长的显示字符串maxLeftWidth，之后draw每一行字符，右边的描述从maxLeftWidth开始draw
* 当一行显示不完全时，折行并且空出maxLeftWidth的空格长度
*/
public class TypographyView1 extends TextView {
private Paint leftPaint = new Paint();
private Paint rightPaint = new Paint();
private int fullWidth;
private float textSize;
private JSONArray array;
private int middlePadding = 0;
float maxLeftWidth = 0;
int itemSize = 0;
public TypographyView1(Context context) {
super(context);
init();
}
public TypographyView1(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public TypographyView1(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
textSize = getResources().getDimensionPixelSize(R.dimen.text_size_13);
leftPaint.setAntiAlias(true);
leftPaint.setTextSize(textSize);
leftPaint.setColor(getResources().getColor(R.color.color_black_999999));
rightPaint.setAntiAlias(true);
rightPaint.setTextSize(textSize);
rightPaint.setColor(getResources().getColor(R.color.color_black));
middlePadding = getResources().getDimensionPixelSize(R.dimen.padding_value);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
fullWidth = getWidth();// 整个textView的宽度
}
public void setText(JSONArray array) {
this.array = array;
if (array != null) {
try {
int size = itemSize = array.length();
for (int i = 0; i < size; ++i) {
JSONArray o = (JSONArray) array.get(i);
String key = o.getString(0);
String value = o.getString(1);
if (TextUtils.isEmpty(key) || TextUtils.isEmpty(value)) {
itemSize--;
continue;
}
float curWidth = leftPaint.measureText(key);
if (curWidth > maxLeftWidth) {
maxLeftWidth = curWidth;
}
}
maxLeftWidth = maxLeftWidth + middlePadding;
invalidate();
} catch (Exception e) {
}
}
}
boolean setHeight = false;
@Override
protected void onDraw(Canvas canvas) {
if (array == null) {
return;
}
int lineCount = 0;
try {
JSONArray item;
float offsetY;
for (int i = 0; i < itemSize; ++i) {
item = (JSONArray) array.get(i);
offsetY = (lineCount + 1) * textSize;
canvas.drawText(item.getString(0), 0, offsetY, leftPaint);
String value = item.getString(1);
float valueWidth = rightPaint.measureText(value);
if (valueWidth > fullWidth - maxLeftWidth) {// 一行显示不完
char[] textCharArray = value.toCharArray();
float charWidth;
float drawWidth = maxLeftWidth;
for (int j = 0; j < textCharArray.length; j++) {
charWidth = rightPaint.measureText(textCharArray, j, 1);
if (fullWidth - drawWidth < charWidth) {
lineCount++;
drawWidth = maxLeftWidth;
offsetY += textSize;
}
canvas.drawText(textCharArray, j, 1, drawWidth, offsetY, rightPaint);
drawWidth += charWidth;
}
} else {
canvas.drawText(value, maxLeftWidth, offsetY, rightPaint);
}
lineCount += 2;
}
if (!setHeight) {
setHeight((lineCount + 1) * (int) textSize);
setHeight = true;
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
添加了setText(JSONArray array)作为数据输入，并且在这里面测量了左边title的最大宽度，之后调用invalidate触发重绘，在onSizeChanged获取整个控件的宽度，重绘会调用onDraw函数，这里不需要调用super函数，TextView的onDraw函数做了非常多的操作，解析传入的数据，分别一行一行调用canvas来进行drawText操作，当绘制描述时，先计算宽度，如果超过剩余控件说明需要换行，最后调用setHeight设置高度，这个加一个判断条件，因为会触发requestLayout()进行重新布局和invalidate()进行重绘，如果不加判断会一直重绘。
方案2
方式2与方式1差不多，不同为所有计算都在onDraw函数中：
/**
* 该方式与方式1很类似，只是所有的计算都放在了onDraw方法中。
*/
public class TypographyView2 extends TextView {
private Paint paint1 = new Paint();
private Paint paint2 = new Paint();
private int middlePadding = 0;
int width;
private float textSize;
private JSONArray array;
public TypographyView2(Context context) {
super(context);
init();
}
public TypographyView2(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public TypographyView2(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
textSize = getResources().getDimensionPixelSize(R.dimen.text_size_13);
paint1.setAntiAlias(true);
paint1.setTextSize(textSize);
paint1.setColor(getResources().getColor(R.color.color_black_999999));
paint2.setAntiAlias(true);
paint2.setTextSize(textSize);
paint2.setColor(getResources().getColor(R.color.color_black));
middlePadding = getResources().getDimensionPixelSize(R.dimen.padding_value);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
width = getWidth();// 整个textView的宽度
}
public void setText(JSONArray array) {
this.array = array;
if (array != null) {
invalidate();
}
}
boolean setHeight = false;
@Override
protected void onDraw(Canvas canvas) {
// super.onDraw(canvas);
int lineCount = 0;
int size = array.length();
float maxLeftWidth = 0;
float drawWidth = 0;
try {
for (int i = 0; i < size; ++i) {
JSONArray o = (JSONArray) array.get(i);
String key = o.getString(0);
float v = paint1.measureText(key);
if (v > maxLeftWidth) {
maxLeftWidth = v;
}
}
maxLeftWidth = maxLeftWidth + middlePadding;
for (int i = 0; i < size; ++i) {
JSONArray o = (JSONArray) array.get(i);
String key = o.getString(0);
canvas.drawText(key, 0, (lineCount + 1) * textSize, paint1);
String value = o.getString(1);
char[] textCharArray = value.toCharArray();
float charWidth;
drawWidth = maxLeftWidth;
for (int j = 0; j < textCharArray.length; j++) {
charWidth = paint1.measureText(textCharArray, j, 1);
if (width - drawWidth < charWidth) {
lineCount++;
drawWidth = maxLeftWidth;
}
canvas.drawText(textCharArray, j, 1, drawWidth, (lineCount + 1) * textSize, paint2);
drawWidth += charWidth;
}
lineCount += 2;
}
if (!setHeight) {
setHeight((lineCount + 1) * (int) textSize + 5);
setHeight = true;
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
该方案的实现是不太好的，方案1也是在此基础上进行调整的，在这里放出来只是为了说明，所有的计算不要全部放在onDraw里面，因为该方法可能会反复调用多次，这样就降低了性能。
方案3
将数据源拼接成SpannableString，重写onDraw函数，根据内容draw每一个字符：
/**
* 该方法，是需要显示的内容先拼接成SpannableString，在onDraw方法中获取所有的char字符，一个一个比较
* 当为分号是，表示为key与value的分隔符。
*/
public class TypographyView3 extends TextView {
private Paint leftPaint = new Paint();
private Paint rightPaint = new Paint();
int width;
private String text;
private float textSize;
float maxLeftWidth = 0;
private int middlePadding = 0;
public TypographyView3(Context context) {
super(context);
init();
}
public TypographyView3(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public TypographyView3(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
textSize = getResources().getDimensionPixelSize(R.dimen.text_size_13);
textSize = getResources().getDimensionPixelSize(R.dimen.text_size_13);
leftPaint.setAntiAlias(true);
leftPaint.setTextSize(textSize);
leftPaint.setColor(getResources().getColor(R.color.color_black_999999));
rightPaint.setAntiAlias(true);
rightPaint.setTextSize(textSize);
rightPaint.setColor(getResources().getColor(R.color.color_black));
middlePadding = getResources().getDimensionPixelSize(R.dimen.padding_value);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
width = getWidth();// 整个textView的宽度
}
public void setText(JSONArray data) {
if (data == null) {
return;
}
try {
int size = data.length();
for (int i = 0; i < size; ++i) {
JSONArray o = (JSONArray) data.get(i);
String key = o.getString(0);
float v = leftPaint.measureText(key);
if (v > maxLeftWidth) {
maxLeftWidth = v;
}
}
maxLeftWidth += middlePadding;
SpannableStringBuilder ssb = new SpannableStringBuilder();
for (int i = 0; i < size; ++i) {
addItem((JSONArray) data.get(i), ssb, i != 0);
}
setText(ssb, BufferType.SPANNABLE);
} catch (Exception e) {
}
}
private void addItem(JSONArray item, SpannableStringBuilder ssb, boolean breakLine) {
try {
if (item == null || item.length() == 0) {
return;
}
String key = item.getString(0);
String value = (item.length() >= 2) ? item.getString(1) : "";
if (TextUtils.isEmpty(key) && TextUtils.isEmpty(value)) {
return;
}
if (breakLine) {// 换行
ssb.append("\r\n");
ssb.append("\r\n");
}
SpannableString span = new SpannableString(key);
// span.setSpan(new ForegroundColorSpan(getResources().getColor(R.color.colorAccent)), 0, key
// .length(),
// Spanned.SPAN_INCLUSIVE_EXCLUSIVE);
ssb.append(span);
ssb.append(value);
} catch (JSONException e) {
e.printStackTrace();
}
}
@Override
protected void onDraw(Canvas canvas) {
// super.onDraw(canvas);
int lineCount = 0;
text = this.getText().toString();
if (text == null)
return;
char[] textCharArray = text.toCharArray();
// 已绘的宽度
float drawWidth = 0;
float charWidth;
Paint paint = leftPaint;
for (int i = 0; i < textCharArray.length; i++) {
charWidth = leftPaint.measureText(textCharArray, i, 1);
if (textCharArray[i] == '\n') {
lineCount++;
drawWidth = 0;
paint = leftPaint;
continue;
}
if (width - drawWidth < charWidth) {
lineCount++;
drawWidth = maxLeftWidth;
}
if (i > 1 && textCharArray[i - 1] == ':') {
drawWidth = maxLeftWidth;
paint = rightPaint;
}
canvas.drawText(textCharArray, i, 1, drawWidth, (lineCount + 1) * textSize, paint);
drawWidth += charWidth;
}
//may be need set height
//setHeight((lineCount + 1) * (int) textSize + 5);
}
}
这里先计算左边title的最大宽度，同时将所有的数据拼接成一个SpannableStringBuilder，调用setText函数会触发重绘，在onDraw函数中进行处理，由于未重新super函数，因此SpannableString的setSpan函数失效，该方案主要根据分隔符来进行分割，因此分隔符需要唯一。
方案4
采用GridLayout方式实现，但是原始控件有展示问题，因此对此进行了修改：
public class Typography4Activity extends BaseActivity {
public static void start(Context context) {
Intent intent = new Intent();
intent.setClass(context, Typography4Activity.class);
context.startActivity(intent);
}
private LinearLayout root;
private Paint leftPaint = new Paint();
private float textSize;
private float maxLeftWidth;
private int middlePadding = 0;
private float maxRightWidth;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
root = (LinearLayout) LayoutInflater.from(this).inflate(R.layout.activity_typography4, null);
setContentView(root);
initPaint();
findViews();
loadData();
}
private void initPaint() {
textSize = getResources().getDimensionPixelSize(R.dimen.text_size_13);
leftPaint.setAntiAlias(true);
leftPaint.setTextSize(textSize);
leftPaint.setColor(getResources().getColor(R.color.color_black_999999));
middlePadding = getResources().getDimensionPixelSize(R.dimen.padding_value);
}
private void findViews() {
}
private void loadData() {
addGridLayout(DataSource.getArray());
TextView view = new TextView(this);
view.setText("修改后的实现");
view.setGravity(Gravity.CENTER);
view.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 160));
root.addView(view);
addModifyGridLayout(DataSource.getArray());
}
private void addGridLayout(JSONArray data) {
try {
GridLayout layout = createGridLayout();
int size = data.length();
for (int i = 0; i < size; ++i) {
JSONArray item = (JSONArray) data.get(i);
String key = item.getString(0);
String value = (item.length() >= 2) ? item.getString(1) : "";
GridLayout.Spec row = GridLayout.spec(i);
GridLayout.Spec col1 = GridLayout.spec(0);
GridLayout.Spec col2 = GridLayout.spec(1);
GridLayout.LayoutParams params = new GridLayout.LayoutParams(row, col1);
TextView title = getLeftTextView(key);
layout.addView(title, params);
params = new GridLayout.LayoutParams(row, col2);
TextView desc = getRightTextView(value);
layout.addView(desc, params);
}
root.addView(layout);
} catch (Exception e) {
}
}
@NonNull
private TextView getRightTextView(String value) {
TextView desc = new TextView(this);
desc.setTextSize(13);
desc.setTextColor(getResources().getColor(R.color.black));
desc.setText(value);
return desc;
}
@NonNull
private TextView getLeftTextView(String key) {
TextView title = new TextView(this);
title.setText(key);
title.setPadding(0, middlePadding, middlePadding, 0);
title.setTextColor(getResources().getColor(R.color.color_black_999999));
title.setTextSize(13);
return title;
}
private void addModifyGridLayout(JSONArray data) {
try {
calculateLeftMaxWidth(data);
GridLayout layout = createGridLayout();
int size = data.length();
for (int i = 0; i < size; ++i) {
JSONArray item = (JSONArray) data.get(i);
GridLayout.Spec row = GridLayout.spec(i);
String key = item.getString(0);
GridLayout.Spec col1 = GridLayout.spec(0);
GridLayout.LayoutParams params = new GridLayout.LayoutParams(row, col1);
TextView title = getLeftTextView(key);
layout.addView(title, params);
String value = (item.length() >= 2) ? item.getString(1) : "";
GridLayout.Spec col2 = GridLayout.spec(1);
params = new GridLayout.LayoutParams(row, col2);
TextView desc = getRightTextView(value);
params.width = (int) maxRightWidth;
params.height = ViewGroup.LayoutParams.WRAP_CONTENT;
layout.addView(desc, params);
}
root.addView(layout);
} catch (Exception e) {
}
}
private void calculateLeftMaxWidth(JSONArray data) {
try {
DisplayUtil.init(this);// 这个可以在应用程序起来的时候init
int size = data.length();
for (int i = 0; i < size; ++i) {
JSONArray o = (JSONArray) data.get(i);
String key = o.getString(0);
String value = o.getString(1);
if (TextUtils.isEmpty(key) || TextUtils.isEmpty(value)) {
continue;
}
float curWidth = leftPaint.measureText(key);
if (curWidth > maxLeftWidth) {
maxLeftWidth = curWidth;
}
}
maxLeftWidth = maxLeftWidth + middlePadding;
maxRightWidth = DisplayUtil.screenWidth - DisplayUtil.dp2px(this, 32 + 10) - maxLeftWidth;
} catch (Exception e) {
}
}
private GridLayout createGridLayout() {
GridLayout layout = new GridLayout(this);
layout.setColumnCount(2);
//layout.setRowCount(5);
layout.setOrientation(GridLayout.HORIZONTAL);
return layout;
}
}
如果直接创建一个GridLayout，里面添加每一项，如果描述过长都导致显示不全，这个是系统的一个bug，计算的宽度有问题，因此需要对此方案进行更改。
更改方式为先计算左边占用的最大宽度，在添加右边的项时，设置布局参数控制最大的长度。
方案5
采用每一行一个布局，手动一行一行进行添加：
public class Typography5Activity extends BaseActivity {
public static void start(Context context) {
Intent intent = new Intent();
intent.setClass(context, Typography5Activity.class);
context.startActivity(intent);
}
private LinearLayout root;
private Paint leftPaint = new Paint();
private float textSize;
private float maxLeftWidth;
private int middlePadding = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
root = (LinearLayout) LayoutInflater.from(this).inflate(R.layout.activity_typography5, null);
setContentView(root);
initPaint();
loadData();
}
private void initPaint() {
textSize = getResources().getDimensionPixelSize(R.dimen.text_size_13);
leftPaint.setAntiAlias(true);
leftPaint.setTextSize(textSize);
leftPaint.setColor(getResources().getColor(R.color.color_black_999999));
middlePadding = getResources().getDimensionPixelSize(R.dimen.padding_value);
}
private void loadData() {
JSONArray array = DataSource.getArray();
calculateLeftMaxWidth(array);
if (array != null) {
try {
int size = array.length();
for (int i = 0; i < size; ++i) {
JSONArray o = (JSONArray) array.get(i);
String key = o.getString(0);
String value = o.getString(1);
addItem(key, value);
}
} catch (Exception e) {
}
}
}
private void calculateLeftMaxWidth(JSONArray data) {
try {
int size = data.length();
for (int i = 0; i < size; ++i) {
JSONArray o = (JSONArray) data.get(i);
String key = o.getString(0);
String value = o.getString(1);
if (TextUtils.isEmpty(key) || TextUtils.isEmpty(value)) {
continue;
}
float curWidth = leftPaint.measureText(key);
if (curWidth > maxLeftWidth) {
maxLeftWidth = curWidth;
}
}
maxLeftWidth = maxLeftWidth + middlePadding;
} catch (Exception e) {
}
}
private void addItem(String key, String value) {
LinearLayout layout = getItemLayout();
TextView left = (TextView) layout.findViewById(R.id.left);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
params.width = (int) maxLeftWidth;
left.setLayoutParams(params);
left.setText(key);
TextView right = (TextView) layout.findViewById(R.id.right);
right.setText(value);
root.addView(layout);
}
private LinearLayout getItemLayout() {
LinearLayout layout = (LinearLayout) LayoutInflater.from(this).inflate(R.layout.compose_item_layout, null);
return layout;
}
}
改方案也需要先计算左边的最大占用宽度，来设置右边占用的大小，每一项的布局如下：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal"
android:paddingTop="@dimen/text_padding_10"
tools:context=".activity.Typography1Activity">
<TextView
android:id="@+id/left"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="@dimen/text_padding_10"
android:textColor="@color/color_black_999999"
android:textSize="@dimen/text_size_13"/>
<TextView
android:id="@+id/right"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textColor="@color/black"
android:textSize="@dimen/text_size_13"/>
</LinearLayout>
每一行有两个TextView，左边宽度为自适应，右边占据剩下左右的位置，在计算出左边最大宽度后，重新设置左边每一个TextView占用的宽度。
方案6
方式与1差不多，但是不在继承TextView，而是直接继承View:
public class TypographyView4 extends View {
private Paint leftPaint = new Paint();
private Paint rightPaint = new Paint();
private int fullWidth;
private float textSize;
private JSONArray array;
private int middlePadding = 0;
float maxLeftWidth = 0;
int itemSize = 0;
public TypographyView4(Context context) {
super(context);
init();
}
public TypographyView4(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public TypographyView4(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
textSize = getResources().getDimensionPixelSize(R.dimen.text_size_13);
leftPaint.setAntiAlias(true);
leftPaint.setTextSize(textSize);
leftPaint.setColor(getResources().getColor(R.color.color_black_999999));
rightPaint.setAntiAlias(true);
rightPaint.setTextSize(textSize);
rightPaint.setColor(getResources().getColor(R.color.color_black));
middlePadding = getResources().getDimensionPixelSize(R.dimen.padding_value);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
fullWidth = getWidth();// 整个textView的宽度
}
public void setText(JSONArray array) {
this.array = array;
if (array != null) {
try {
int size = itemSize = array.length();
for (int i = 0; i < size; ++i) {
JSONArray o = (JSONArray) array.get(i);
String key = o.getString(0);
String value = o.getString(1);
if (TextUtils.isEmpty(key) || TextUtils.isEmpty(value)) {
itemSize--;
continue;
}
float curWidth = leftPaint.measureText(key);
if (curWidth > maxLeftWidth) {
maxLeftWidth = curWidth;
}
}
maxLeftWidth = maxLeftWidth + middlePadding;
invalidate();
} catch (Exception e) {
}
}
}
@Override
protected void onDraw(Canvas canvas) {
if (array == null) {
return;
}
int lineCount = 0;
try {
JSONArray item;
float offsetY;
for (int i = 0; i < itemSize; ++i) {
item = (JSONArray) array.get(i);
offsetY = (lineCount + 1) * textSize;
canvas.drawText(item.getString(0), 0, offsetY, leftPaint);
String value = item.getString(1);
float valueWidth = rightPaint.measureText(value);
if (valueWidth > fullWidth - maxLeftWidth) {// 一行显示不完
char[] textCharArray = value.toCharArray();
float charWidth;
float drawWidth = maxLeftWidth;
for (int j = 0; j < textCharArray.length; j++) {
charWidth = rightPaint.measureText(textCharArray, j, 1);
if (fullWidth - drawWidth < charWidth) {
lineCount++;
drawWidth = maxLeftWidth;
offsetY += textSize;
}
canvas.drawText(textCharArray, j, 1, drawWidth, offsetY, rightPaint);
drawWidth += charWidth;
}
} else {
canvas.drawText(value, maxLeftWidth, offsetY, rightPaint);
}
lineCount += 2;
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
该方案主要继承自View，不再继承TextView，由于在在上述方案中不在调用super，因此TextView已经退化为一个View,因此直接继承View。
总结
因为左边的宽度不确定，因此所有的方案都进行了同样的一个操作，就是测量了左边显示的最大宽度，后续的操作再根据该宽度进行调整。上述的方案中1，2，3，6都只需用一个View来进行显示，4，5都需要多个View进行显示。
完整的代码可以在查看链接上进行查看。
以上就是本文的全部内容，希望对大家的学习有所帮助。
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