Activity启动过程中获取组件宽高的五种方式-白红宇

Activity启动过程中获取组件宽高的五种方式

阅读量：5058 次

发布时间：2019-06-12

本文共 2622 字，大约阅读时间需要 8 分钟。

第一种:(重写Activity的onWindowFocusChanged方法)

/** * 重写Acitivty的onWindowFocusChanged方法 */ @Overridepublic void onWindowFocusChanged(boolean hasFocus) {super.onWindowFocusChanged(hasFocus);/** * 当hasFocus为true的时候，说明Activity的Window对象已经获取焦点，进而Activity界面已经加载绘制完成 */if (hasFocus) {int widht = titleText.getWidth();int height = titleText.getHeight(); Log.i(TAG, "onWindowFocusChanged width:" + widht + " " + " height:" + height; } }

第二种:(为组件添加OnGlobalLayoutListener事件监听)

/** * 为Activity的布局文件添加OnGlobalLayoutListener事件监听，当回调到onGlobalLayout方法的时候我们通过getMeasureHeight和getMeasuredWidth方法可以获取到组件的宽和高 */private void initOnLayoutListener() {final ViewTreeObserver viewTreeObserver = this.getWindow().getDecorView().getViewTreeObserver();viewTreeObserver.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {@Overridepublic void onGlobalLayout() {Log.i(TAG, "开始执行onGlobalLayout().........");int height = titleText.getMeasuredHeight(); int width = titleText.getMeasuredWidth(); Log.i(TAG, "height:" + height + " width:" + width); // 移除GlobalLayoutListener监听 MainActivity.this.getWindow().getDecorView().getViewTreeObserver().removeOnGlobalLayoutListener(this); } }); }

第三种:(为组件添加OnPreDrawListener事件监听)

/** * 初始化viewTreeObserver事件监听,重写OnPreDrawListener获取组件高度 */private void initOnPreDrawListener() {final ViewTreeObserver viewTreeObserver = this.getWindow().getDecorView().getViewTreeObserver();viewTreeObserver.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {@Overridepublic boolean onPreDraw() {Log.i(TAG, "开始执行onPreDraw().........");int height = titleText.getMeasuredHeight(); int width = titleText.getMeasuredWidth(); Log.i(TAG, "height:" + height + " width:" + width); // 移除OnPreDrawListener事件监听 MainActivity.this.getWindow().getDecorView().getViewTreeObserver().removeOnPreDrawListener(this); return true; } }); }

第四种:(使用View.post方法获取组件的宽高)

/** * 使用View的post方法获取组件的宽度和高度 */private void initViewHandler() {titleText.post(new Runnable() {@Overridepublic void run() {int width = titleText.getWidth();int height = titleText.getHeight();Log.i(TAG, "initViewHandler height:" + height + "  width:" + width); } }); }

第五种:(通过Handler对象使用异步消息获取组件的宽高)

/** * 在onCreate方法中发送异步消息，在handleMessage中获取组件的宽高 */private Handler mHandler = new Handler() {@Overridepublic void handleMessage(Message msg) {if (msg.what == 101) {int width = titleText.getWidth();int height = titleText.getHeight();Log.i(TAG, "initViewHandler height:" + height + "  width:" + width); } } };