Android 中使用EditText 点击全选再次点击取消全选功能

android:focusable="true"
android:selectAllOnFocus="true"

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
  android:paddingLeft="@dimen/activity_horizontal_margin"
  android:paddingRight="@dimen/activity_horizontal_margin"
  android:paddingTop="@dimen/activity_vertical_margin"
  tools:context="com.example.edittexttest.MainActivity">
  <EditText
    android:id="@+id/edit"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:focusable="true"
    android:selectAllOnFocus="true"
    />
</RelativeLayout>

package com.example.edittexttest;
import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
  private EditText editText;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    editText = (EditText) findViewById(R.id.edit);
    editText.setText("click to select all");
    editText.clearFocus();
    editText.setFocusableInTouchMode(false);
    editText.setOnTouchListener(new View.OnTouchListener() {
      @Override
      public boolean onTouch(View view, MotionEvent motionEvent) {
        if (motionEvent.getAction() == MotionEvent.ACTION_UP) {
          editText.setFocusableInTouchMode(true);
          editText.requestFocus();
          editText.setText("click to select all");
          editText.selectAll();
        }
        return false;
      }
    });
  }
  @Override
  public boolean dispatchTouchEvent(MotionEvent ev) {
    if (ev.getAction() == MotionEvent.ACTION_DOWN) {
      View v = getCurrentFocus();
      if (isShouldHideInput(v, ev)) {
        InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        if (imm.isActive()) {
          imm.hideSoftInputFromWindow(v.getWindowToken(), 0);
        }
      }
      return super.dispatchTouchEvent(ev);
    }
    // Necessary
    if (getWindow().superDispatchTouchEvent(ev)) {
      return true;
    }
    editText.clearFocus();
    editText.setFocusableInTouchMode(false);
    return onTouchEvent(ev);
  }
  public boolean isShouldHideInput(View v, MotionEvent event) {
    if (v != null && (v instanceof EditText)) {
      int[] leftTop = { 0, 0 };
      //get location of TextView
      v.getLocationInWindow(leftTop);
      int left = leftTop[0];
      int top = leftTop[1];
      int bottom = top + v.getHeight();
      int right = left + v.getWidth();
      if (event.getX() > left && event.getX() < right
          && event.getY() > top && event.getY() < bottom) {
        return false;
      } else {
        return true;
      }
    }
    return false;
  }
}

editText.setFocusableInTouchMode(true);
editText.requestFocus();