Android自定义控件之翻转按钮的示例代码

时间：2022-11-27 10:20:48|栏目：Android代码|点击：次

本文介绍了Android自定义控件之翻转按钮的示例代码，分享给大家，具体如下：

先看一下效果

一.先定义控件的基本结构

这里我们定义一个容器，所以是在ViewGroup的基础上扩展。

简单起见，直接使用扩展自ViewGroup的LinearLayout，并将我们的控件扩展自LinearLayout。

1.按钮的基本布局如下

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:orientation="vertical">
  <FrameLayout
    android:id="@+id/mButton"
    android:background="@color/colorPrimary"
    android:padding="5dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
      android:id="@+id/buttonText"
      android:text="FLIPPED BUTTON"
      android:textColor="@android:color/white"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" />
  </FrameLayout>
</LinearLayout>

2.自定义控件开门三步走

构造函数，onMeasure，onLayout

package net.codepig.customviewdemo.view;

import android.content.Context;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.LinearLayout;

import net.codepig.customviewdemo.R;

public class flippedButton extends LinearLayout {
  private Context mContext;
  private int mWidth;//容器的宽度
  private int mHeight;//容器的高度
  private TextView buttonText;
  private FrameLayout mButton;
  public flippedButton(Context context){
    super(context);
    this.mContext = context;
    init(context);
  }

  public flippedButton(Context context, AttributeSet attrs) {
    super(context, attrs);
    this.mContext = context;
    init(context);
  }

  public flippedButton(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    this.mContext = context;
    init(context);
  }

  private void init(Context context){
    //使用xml中的布局
    LayoutInflater.from(context).inflate(R.layout.filpped_button,this, true);
    mButton=findViewById(R.id.mButton);
    buttonText=findViewById(R.id.buttonText);
  }

  //测量子View
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    measureChildren(widthMeasureSpec, heightMeasureSpec);
    mWidth = getMeasuredWidth();
    mHeight = getMeasuredHeight();

    //遍历子元件
//    int childCount = this.getChildCount();
//    for (int i = 0; i < childCount; i++) {
//      View child = this.getChildAt(i);
//      this.measureChild(child, widthMeasureSpec, heightMeasureSpec);
//      int cw = child.getMeasuredWidth();
//      int ch = child.getMeasuredHeight();
//    }
  }

  //排列子View的位置
  @Override
  protected void onLayout(boolean changed, int l, int t, int r, int b) {
    int childTop = 0;
    for (int i = 0; i < getChildCount(); i++) {
      View child = getChildAt(i);
      if (child.getVisibility() != GONE) {
        child.layout(0, childTop,child.getMeasuredWidth(), childTop + child.getMeasuredHeight());
        childTop = childTop + child.getMeasuredHeight();
      }
    }
  }
}

3.在Activity的布局中直接使用

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_gravity="center"
  android:orientation="vertical">
  <net.codepig.customviewdemo.view.flippedButton
    android:id="@+id/flippedButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">
  </net.codepig.customviewdemo.view.flippedButton>
</LinearLayout>

现在可以看到一个最基本的自定义控件已经可以使用了。

二.接下来是重点，控件真正“自定义”的部分。

1.添加自定义事件

a.先定义自定义事件接口

/**
   * 定义接口
   */
  public interface IMyClick{
    public void onMyClick(String str);
  }

  /**
   * 初始化接口变量
   */
  IMyClick iMyClick=null;

  /**
   * 自定义事件监听
   * @param _iMyClick
   */
  public void setOnMyClickListener(IMyClick _iMyClick){
    iMyClick=_iMyClick;
  }

b.添加按钮点击事件的监听并调用接口传参

mButton.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
        iMyClick.onMyClick("clicked me");
        flipMe();
      }
    });

c.父级Activity监听事件

fButton=(flippedButton) findViewById(R.id.flippedButton);
    fButton.setOnMyClickListener(new flippedButton.IMyClick(){
      @Override
      public void onMyClick(String str) {
        Log.d(LOG_TAG,str);
      }
    });

2.绘制按钮翻转的动画

这里的3d变换需要用到Camera（android.graphics.Camera）、Matrix。

这里可以想象成用Camera拍摄原件的图形，并将拍摄得到的bitmap传入matrix再绘制到Canvas。

而改变Camera镜头角度就可以得到缩放变形后的图像以实现3d效果。

参考官方demo里的这个工具类的范例Rotate3dAnimation.java（其实是照搬)

a.先建一个3d变换的工具类:

package net.codepig.customviewdemo.model;

import android.graphics.Camera;//注意使用的是graphics里的而不是hardware里的
import android.view.animation.Animation;
import android.view.animation.Transformation;
import android.graphics.Matrix;

/**
 * An animation that rotates the view on the Y axis between two specified angles.
 * This animation also adds a translation on the Z axis (depth) to improve the effect.
 */
public class Rotate3dAnimation extends Animation {
  private final float mFromDegrees;
  private final float mToDegrees;
  private final float mCenterX;
  private final float mCenterY;
  private final float mDepthZ;
  private final boolean mReverse;
  private Camera mCamera;

  /**
   * Creates a new 3D rotation on the Y axis. The rotation is defined by its
   * start angle and its end angle. Both angles are in degrees. The rotation
   * is performed around a center point on the 2D space, definied by a pair
   * of X and Y coordinates, called centerX and centerY. When the animation
   * starts, a translation on the Z axis (depth) is performed. The length
   * of the translation can be specified, as well as whether the translation
   * should be reversed in time.
   *
   * @param fromDegrees the start angle of the 3D rotation
   * @param toDegrees the end angle of the 3D rotation
   * @param centerX the X center of the 3D rotation
   * @param centerY the Y center of the 3D rotation
   * @param reverse true if the translation should be reversed, false otherwise
   */
  public Rotate3dAnimation(float fromDegrees, float toDegrees, float centerX, float centerY, float depthZ, boolean reverse) {
    mFromDegrees = fromDegrees;
    mToDegrees = toDegrees;
    mCenterX = centerX;
    mCenterY = centerY;
    mDepthZ = depthZ;
    mReverse = reverse;
  }

  @Override
  public void initialize(int width, int height, int parentWidth, int parentHeight) {
    super.initialize(width, height, parentWidth, parentHeight);
    mCamera = new Camera();
  }

  /**
   *
   * @param interpolatedTime 动画时间点，类似百分比
   * @param t
   */
  @Override
  protected void applyTransformation(float interpolatedTime, Transformation t) {
    final float fromDegrees = mFromDegrees;
    float degrees = fromDegrees + ((mToDegrees - fromDegrees) * interpolatedTime);

    final float centerX = mCenterX;
    final float centerY = mCenterY;
    final Camera camera = mCamera;

    final Matrix matrix = t.getMatrix();

    camera.save();
    if (mReverse) {//远离
      camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);
    } else {//靠近
      camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));
    }
    camera.rotateY(degrees);
    camera.getMatrix(matrix);
    camera.restore();

    //移动旋转中心到布局中心
    matrix.preTranslate(-centerX, -centerY);
    matrix.postTranslate(centerX, centerY);
  }
}

注意：使用的是graphics里的Camera而不是hardware里的

注意：其中的centerX和centerY是中心点位置。由于Camera的变换是以（0,0）点为原点，所以需要进行变换。

b.调用这个Animation

final Rotate3dAnimation animation = new Rotate3dAnimation(0, 180,centerX, centerY, 0, true);
      animation.setDuration(500);//动画持续时间，默认为0
      animation.setFillAfter(true);//这个false的话动画完了会复原
      mButton.startAnimation(animation);

嗯，这样按钮就翻转了。

3.接下来做出按钮切换的效果

这里有两种方法。可以使用两个按钮一起翻转，也可以一个按钮翻90后改变样式再翻回来。

我这里使用一个按钮的方案。

先设置两种状态的动画。（注意在onMeasure后设置，不然中心位置定位到0，0了）

    animationF = new Rotate3dAnimation(0, 90,centerX, centerY, 0, true);
    animationF.setDuration(500);//动画持续时间，默认为0
    animationF.setFillAfter(true);//这个false的话动画完了会复原

    animationB = new Rotate3dAnimation(-90, 0,centerX, centerY, 0, true);
    animationB.setDuration(500);
    animationB.setFillAfter(true);

给0-90度翻转的动画增加监听，动画完成时根据状态标识改变样式和文字，然后再从-90-0度翻转的动画。

animationF.setAnimationListener(new Animation.AnimationListener() {
      @Override
      public void onAnimationStart(Animation animation) {

      }

      @Override
      public void onAnimationEnd(Animation animation) {
        if (!showBack) {
          buttonText.setText("BACK BUTTON");
          mButton.setBackgroundColor(getResources().getColor(R.color.colorAccent));
        } else { // 背面朝上
          buttonText.setText("FRONT BUTTON");
          mButton.setBackgroundColor(getResources().getColor(R.color.colorPrimary));
        }
        mButton.startAnimation(animationB);
      }

      @Override
      public void onAnimationRepeat(Animation animation) {

      }
    });

三.一个问题：显示不全

翻转的时候发现3d变换扩大了的部分超过了空间原先的显示区域而没有显示出来。

这里涉及到margin和padding的处理。

先给mButton的布局增加margin。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:orientation="vertical">
  <FrameLayout
    android:id="@+id/mButton"
    android:layout_margin="100dp"
    android:background="@color/colorPrimary"
    android:padding="5dp"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">
    <TextView
      android:id="@+id/buttonText"
      android:text="FRONT BUTTON"
      android:gravity="center"
      android:textColor="@android:color/white"
      android:layout_width="100dp"
      android:layout_height="50dp" />
  </FrameLayout>
</LinearLayout>

在onMeasure处理自定义view的margin和padding。

@Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    measureChildren(widthMeasureSpec, heightMeasureSpec);
    centerX=mButton.getMeasuredWidth()/ 2;
    centerY=mButton.getMeasuredHeight() / 2;

    mWidth = 0;
    mHeight = 0;
    //margin
    marginLeft = 0;
    marginTop = 0;
    marginRight = 0;
    marginBottom = 0;
    //padding
    paddingLeft = getPaddingLeft();
    paddingTop = getPaddingTop();
    paddingRight = getPaddingRight();
    paddingBottom = getPaddingBottom();
    int childCount = getChildCount();
    for (int i = 0; i < childCount; i++) {
      View childView = getChildAt(i);
      MarginLayoutParams lp = (MarginLayoutParams) childView.getLayoutParams();
      measureChild(childView, widthMeasureSpec, heightMeasureSpec);
      viewsHeight += childView.getMeasuredHeight();
      viewsWidth = Math.max(viewsWidth, childView.getMeasuredWidth());
      marginLeft = Math.max(0,lp.leftMargin);//最大左边距
      marginTop += lp.topMargin;//上边距之和
      marginRight = Math.max(0,lp.rightMargin);//最大右边距
      marginBottom += lp.bottomMargin;//下边距之和
    }

    mWidth = getMeasuredWidth() + paddingLeft + paddingRight + marginLeft + marginRight;
    mHeight = getMeasuredHeight() + paddingBottom + paddingTop + marginTop + marginBottom;
    setMeasuredDimension(measureWidth(widthMeasureSpec, mWidth), measureHeight(heightMeasureSpec, mHeight));

    //动画
    animationF = new Rotate3dAnimation(0, 90,centerX, centerY, 0, true);
    animationF.setDuration(500);//动画持续时间，默认为0
    animationF.setFillAfter(true);//这个false的话动画完了会复原
    animationB = new Rotate3dAnimation(-90, 0,centerX, centerY, 0, true);
    animationB.setDuration(500);
    animationB.setFillAfter(true);

    animationF.setAnimationListener(new Animation.AnimationListener() {
      @Override
      public void onAnimationStart(Animation animation) {
      }

      @Override
      public void onAnimationEnd(Animation animation) {
        if (showBack) {
          buttonText.setText("BACK BUTTON");
          mButton.setBackgroundColor(getResources().getColor(R.color.colorAccent));
        } else { // 背面朝上
          buttonText.setText("FRONT BUTTON");
          mButton.setBackgroundColor(getResources().getColor(R.color.colorPrimary));
        }
        mButton.startAnimation(animationB);
      }

      @Override
      public void onAnimationRepeat(Animation animation) {
      }
    });
  }

相关github项目地址：flippedButton

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