Android开发动态获取控件宽高

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 最近做项目自定义控件时候想获取控件中元素参数，但各种失败，网上搜了下，自己也总结一下。

 package com.example.androidtest_02;

 import android.app.Activity;
 import android.content.Intent;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.Menu;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.ViewTreeObserver;
 import android.view.ViewTreeObserver.OnGlobalLayoutListener;
 import android.view.WindowManager.LayoutParams;
 import android.widget.Button;
 import android.widget.TextView;

 /**
  *
  * 这个activity测试 ： 1.Activity的生命周期 2.程序动态获取控件的宽高
  *
  * 结论：activity启动时候：onCreate()-->onStart()--->onResum()-->onAttachedToWindow()-->
  * onWindowFocusChanged()
  *
  * 当另外一个activity be in front of
  * 的时候：onPause()--->onWindowFocusChanged()-->onStop()
  *
  * 当第一个activity恢复到最前面时候：onRestart()--->onStart()--->onResum()--->
  * onWindowFocusChanged()
  *
  * 当activityfinish的时候：onPause()-->onWindowFocusChanged()-->onStop()-->onDestroy(
  * )
  *
  *
  * onAttachedToWindow()此时打印出了控件宽高，其他地方的打印为0 ，so,activity全面加载完了之后才会获取到控件的宽高，
  * 当我们需要获取控件的宽高时，需要等activity加载完。
  *
  * 第二种与第三种方式：即使实在oncreate()方法里面声明了，回调里面的内容也只能在onResume()方法被调用后才能得到执行。
  */
 public class MainActivity extends Activity implements OnClickListener {

     public void printLog(String s) {

         Log.e("-------------------------------", s);
     }

     Button btn1;
     Button btn2;
     TextView textview1;

     /**
      * 第一种获取宽高的方式。
      */
     int w = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
     int h = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         btn1 = (Button) findViewById(R.id.btn1);
         btn1.setOnClickListener(this);
         btn2 = (Button) findViewById(R.id.btn2);
         textview1 = (TextView) findViewById(R.id.textview1);

         textview1.measure(w, h);
         // int height =textview1.getMeasuredHeight();
         // int width =textview1.getMeasuredWidth();
         printLog("直接获取宽高：width:" + textview1.getWidth() + "---->height:"
                 + textview1.getHeight());
         printLog("使用mesure()获取宽高：width:" + textview1.getWidth()
                 + "---->height:" + textview1.getHeight());

         // 即使实在oncreate()方法里面声明了，回调里面的内容也只能在onResume()方法被调用后才能得到执行。

         // 第二种获取宽高的方式
         ViewTreeObserver viewTreeObserver = textview1.getViewTreeObserver();
         viewTreeObserver
                 .addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {

                     @Override
                     public boolean onPreDraw() {

                         printLog("使用ViewTreeObserver 获取宽高：width:"
                                 + textview1.getMeasuredWidth() + "---->height:"
                                 + textview1.getMeasuredHeight());

                         return true;
                     }
                 });

         // 第三种获取宽高的方式
         ViewTreeObserver vtb1 = textview1.getViewTreeObserver();
         vtb1.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

             @Override
             public void onGlobalLayout() {
                 textview1.getViewTreeObserver().addOnGlobalLayoutListener(this);
                 printLog("使用OnGlobalLayoutListener 获取宽高：width:"
                         + textview1.getWidth() + "---->height:"
                         + textview1.getHeight());
             }
         });

     }

     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         // Inflate the menu; this adds items to the action bar if it is present.
         getMenuInflater().inflate(R.menu.activity_main, menu);
         return true;
     }

     @Override
     protected void onStart() {
         super.onStart();
         printLog("onstart()");
         printLog("width:" + textview1.getWidth() + "---->height:"
                 + textview1.getHeight());

     }

     @Override
     protected void onResume() {
         super.onResume();
         printLog("onResume()");
         printLog("width:" + textview1.getWidth() + "---->height:"
                 + textview1.getHeight());
     }

     @Override
     public void onAttachedToWindow() {
         super.onAttachedToWindow();
         printLog("onAttachedToWindow()");
         printLog("width:" + textview1.getWidth() + "---->height:"
                 + textview1.getHeight());
     }

     @Override
     public void onWindowFocusChanged(boolean hasFocus) {
         super.onWindowFocusChanged(hasFocus);
         printLog("onWindowFocusChanged()");
         printLog("width:" + textview1.getWidth() + "---->height:"
                 + textview1.getHeight());// 此时打印出了控件宽高，其他地方的打印为0
     }

     @Override
     protected void onRestart() {
         super.onRestart();
         printLog("onRestart()");
     }

     @Override
     public void onWindowAttributesChanged(LayoutParams params) {
         super.onWindowAttributesChanged(params);
         printLog("onWindowAttributesChanged()");
     }

     @Override
     protected void onPause() {
         super.onPause();
         printLog("onPause()");
     }

     @Override
     protected void onStop() {
         super.onStop();
         printLog("onStop()");
     }

     @Override
     protected void onDestroy() {
         super.onDestroy();
         printLog("onDestroy()");
     }

     @Override
     public void onClick(View v) {

         if (v.equals(btn1)) {
             printLog("+++++++++++++++++++马上要跳转了++++++++++++++++++");
             Intent intent = new Intent(MainActivity.this, Activity1.class);
             startActivity(intent);
         } else if (v.equals(btn2)) {

             printLog("+++++++++++++++++++马上finish了++++++++++++++++++");
             this.finish();
         }
     }

     @Override
     public void onBackPressed() {

         printLog("+++++++++++++++++++我点了返回键，马上要跳转了++++++++++++++++++");

     }

 }