使用FrameLayout实现遮罩层

利用FrameLayout的特性,可以实现一个简单的遮罩层.

<?xml version="1.0" encoding="utf-8"?><FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"        android:id="@+id/layout"        android:layout_width="fill_parent"        android:layout_height="fill_parent"        >        <LinearLayout    android:orientation="vertical"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    >        <Button           android:id="@+id/btn"           android:layout_width="wrap_content"           android:layout_height="wrap_content"           android:layout_alignParentRight="true"           android:text="show"           /><TextView      android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="@string/hello"    /><EditText android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="Mask"    /></LinearLayout></FrameLayout>

package com.ql.app;import android.app.Activity;import android.graphics.Color;import android.os.Bundle;import android.view.Gravity;import android.view.View;import android.view.ViewGroup;import android.view.Window;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.FrameLayout;import android.widget.TextView;public class App extends Activity {private boolean isMask = true;private FrameLayout layout = null;private Button btn = null;private TextView textView = null;public void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.main);initViews();}private void initViews() {layout = (FrameLayout) findViewById(R.id.layout);btn = (Button) findViewById(R.id.btn);btn.setOnClickListener(new MaskListener());}// 按钮监听，显示/隐藏遮罩private class MaskListener implements OnClickListener {public void onClick(View v) {if (isMask) {if(textView==null){textView = new TextView(App.this);textView.setTextColor(Color.BLUE);textView.setTextSize(20);textView.setText("I am a mask.");textView.setGravity(Gravity.CENTER);textView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,ViewGroup.LayoutParams.FILL_PARENT));textView.setBackgroundColor(Color.parseColor("#33FFFFFF"));}btn.setText("show");isMask = false;layout.addView(textView);} else {btn.setText("hide");isMask = true;layout.removeView(textView);}}}}