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);
			}
		}
	}
}

  

使用FrameLayout实现遮罩层