Android开发动态获取控件宽高

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++++++++++++++++++");

	}

}