用過手機360和QQ手機管家等一些軟體的朋友，會發現，在這些應用中，會出現一個懸浮窗體，例如QQ手機管家中打電話的場景：


這種窗體除了會顯示外，還可以移動它的位置，並且一直顯示。除了關閉當前程式外，視窗不會主動消失。其實，它的使用原理也很簡單，就是借用了WindowManager這個管理類來實現的。
注意：要在AndroidManifest.xml中新增使用許可權：

<uses-permission
		android:name="android.permission.SYSTEM_ALERT_WINDOW" />

import android.content.Context;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

public class DesktopLayout extends LinearLayout {

	public DesktopLayout(Context context) {
		super(context);
		setOrientation(LinearLayout.HORIZONTAL);
		LayoutParams mLayoutParams = new LayoutParams(
				LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
		setLayoutParams(mLayoutParams);

		// 顯示的ICON
		ImageView mImageView = new ImageView(context);
		mImageView.setImageResource(R.drawable.icon);
		addView(mImageView, mLayoutParams);

		// 顯示的文字
		TextView mTextView = new TextView(context);
		mTextView.setText("Hello");
		mTextView.setTextSize(30);
		addView(mTextView, mLayoutParams);
	}
}
 

		// 取得系統窗體
		mWindowManager = (WindowManager) getApplicationContext()
				.getSystemService("window");

		// 窗體的佈局樣式
		mLayoutParams = new WindowManager.LayoutParams();

		// 設定窗體顯示型別——TYPE_SYSTEM_ALERT(系統提示)
		mLayoutParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;

		// 設定窗體焦點及觸控：
		// FLAG_NOT_FOCUSABLE(不能獲得按鍵輸入焦點)
		mLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;

		// 設定顯示的模式
		mLayoutParams.format = PixelFormat.RGBA_8888;

		// 設定對齊的方法
		mLayoutParams.gravity = Gravity.TOP | Gravity.LEFT;

		// 設定窗體寬度和高度
		mLayoutParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
		mLayoutParams.height = WindowManager.LayoutParams.WRAP_CONTENT;

		// 設定窗體顯示的位置，否則在螢幕中心顯示
		mLayoutParams.x = 50;
		mLayoutParams.y = 50;
 

mWindowManager.addView(mDesktopLayout, mLayoutParams);

mWindowManager.removeView(mDesktopLayout);

import android.app.Activity;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
import android.view.WindowManager;
import android.widget.Button;

public class DeskTip extends Activity {

	private WindowManager mWindowManager;

	private WindowManager.LayoutParams mLayoutParams;

	private DesktopLayout mDesktopLayout;

	private long starttime;

	/**
	 * 建立懸浮窗體
	 */
	private void createDesktopLayout() {
		mDesktopLayout = new DesktopLayout(this);
		mDesktopLayout.setOnTouchListener(new OnTouchListener() {
			public boolean onTouch(View v, MotionEvent event) {
				onActionMove(event);
				return true;
			}
		});
	}

	/**
	 * 設定WindowManager
	 */
	private void createWindowManager() {
		// 取得系統窗體
		mWindowManager = (WindowManager) getApplicationContext()
				.getSystemService("window");

		// 窗體的佈局樣式
		mLayoutParams = new WindowManager.LayoutParams();

		// 設定窗體顯示型別——TYPE_SYSTEM_ALERT(系統提示)
		mLayoutParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;

		// 設定窗體焦點及觸控：
		// FLAG_NOT_FOCUSABLE(不能獲得按鍵輸入焦點)
		mLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;

		// 設定顯示的模式
		mLayoutParams.format = PixelFormat.RGBA_8888;

		// 設定對齊的方法
		mLayoutParams.gravity = Gravity.TOP | Gravity.LEFT;

		// 設定窗體寬度和高度
		mLayoutParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
		mLayoutParams.height = WindowManager.LayoutParams.WRAP_CONTENT;

		// 設定窗體顯示的位置，否則在螢幕中心顯示
		mLayoutParams.x = 50;
		mLayoutParams.y = 50;
	}

	private void onActionMove(MotionEvent event) {

		if (event.getAction() == MotionEvent.ACTION_DOWN) {
			long end = System.currentTimeMillis() - starttime;
			// 雙擊的間隔在 200ms 到 500ms 之間
			if (end > 200 && end < 500) {
				closeDesk();
				return;
			}
			starttime = System.currentTimeMillis();
		}

		mLayoutParams.x = (int) (event.getRawX() - (mDesktopLayout.getWidth()));
		mLayoutParams.y = (int) (event.getRawY() - (mDesktopLayout.getHeight()));

		mWindowManager.updateViewLayout(mDesktopLayout, mLayoutParams);
	}

	/**
	 * 顯示DesktopLayout
	 */
	private void showDesk() {
		mWindowManager.addView(mDesktopLayout, mLayoutParams);
		finish();
	}

	/**
	 * 關閉DesktopLayout
	 */
	private void closeDesk() {
		mWindowManager.removeView(mDesktopLayout);
		finish();
	}

	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		createWindowManager();
		createDesktopLayout();

		Button btn = (Button) findViewById(R.id.btn);
		btn.setOnClickListener(new OnClickListener() {
			public void onClick(View v) {
				showDesk();
			}
		});
	}
}