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);
      }
    }
  }
}