WindowManager- InvalidDisplayException

最近在瞭解Window及WindowManger,

Window表示一個窗口，是一個抽象類，具體由PhoneWindow實現。

而創建一個Window需要用到WindowManager, WindowManagerImpl,WindowManagerGlobal, ViewRootImpl等等，

最終以View的形式展現給用戶。具體概念不做介紹，分享一個簡單的例子及遇到的問題以及解決的辦法。

解決遇到問題的過程比較重要。

 

最初是想在一個Activity 裏通過WindowManager添加一個View， 例子也是書上的

但是結果FC了， 原因如下

09-14 11:11:37.755  9367  9367 E AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.XX.viewmotiontest02/com.XX.viewmotiontest02.ViewMotionTest02}: android.view.WindowManager$InvalidDisplayException: Unable to add window <a target=_blank href="mailto:android.view.ViewRootImpl$W@259f2ae">android.view.ViewRootImpl$W@259f2ae</a> -- the specified window type is not valid
......
09-14 11:11:37.755  9367  9367 E AndroidRuntime: Caused by:<span style="color:#ff0000;"> android.view.WindowManager$InvalidDisplayException: Unable to add window </span><a target=_blank href="mailto:android.view.ViewRootImpl$W@259f2ae"><span style="color:#ff0000;">android.view.ViewRootImpl$W@259f2ae</span></a><span style="color:#ff0000;"> -- the specified window type is not valid</span>
09-14 11:11:37.755  9367  9367 E AndroidRuntime:  at android.view.ViewRootImpl.setView(ViewRootImpl.java:817)

 

對這種錯誤毫無頭緒，並且是書上的例子。。

百度及谷歌了都沒有類似的問題， 嘗試新啓動一個Service, 然後在Service 裏面再添加一個View， 依然保持同樣的錯誤。

準備放棄的時候，去官方API 瞄了一眼 WindowManager$InvalidDisplayException ，介紹說這個Exception是因爲無法作爲第二個View顯示之類的。。

又看看錯誤 是 window type not valid,  想到了每添加一個View , 都會爲其設置WindowManager.LayoutParms, 其中WindowManager.LayoutParms 就有type屬性。。

而看了創建LayoutParms的代碼：

mLayoutParams = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT,
                <span style="color:#ff0000;">0</span> , 0, PixelFormat.TRANSPARENT); // <span style="color:#ff0000;">w, h, type, flags, format;</span>

 從API上看，LayoutParms對應上面的構造函數中， type 並沒有0這個值的！！！

type: 1~99  應用Window層

type: 1000 ~1999 子Window

type:  2000~2999 系統層 （最頂層）

因此type 爲0 必須報錯！！！！

改成 WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY， 並且添加 uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"

所以，關鍵時候，官方API 還是很有幫助的！！！

 

部分代碼：

package com.XX.viewmotiontest02;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.graphics.PixelFormat;
import android.os.Bundle;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;

public class ViewMotionTest02 extends Activity {
    private static final String LOG_TAG = "ViewMotionTest02";
    private boolean mIsUseService;
    Button mStartBtn;
    Button mFloatingButton;
    WindowManager.LayoutParams mLayoutParams;
    WindowManager mWindowManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d(LOG_TAG,"onCreate ");
        setContentView(R.layout.activity_view_motion_test02);

        mIsUseService = false; // true: Service,  false: Activity
        Log.d(LOG_TAG,"mIsUseService: " + mIsUseService);
        if(mIsUseService) {
            mStartBtn = (Button) findViewById(R.id.startServiceBtn);
            mStartBtn.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.d(LOG_TAG, "onClick");
                    Intent intent = new Intent(getApplicationContext(), ViewMotionService.class);
                    startService(intent);
                }
            });
        } else {
            //mStartBtn.setVisibility(View.INVISIBLE);
            mFloatingButton = new Button(this);
            mFloatingButton.setText("Button In Activity");
            mLayoutParams = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT,
                    WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY , 0, PixelFormat.TRANSPARENT); // w, h, type, flags, format;
            mLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL
                    | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                    | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED;
            mLayoutParams.gravity = Gravity.LEFT | Gravity.TOP;
            mLayoutParams.x = 100;
            mLayoutParams.y = 300;
            mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
            mWindowManager.addView(mFloatingButton,mLayoutParams);
        }

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.d(LOG_TAG,"onDestroy ");
        if(mIsUseService) {
            Intent intent = new Intent(getApplicationContext(), ViewMotionService.class);
            stopService(intent);
        } else{
            mWindowManager.removeView(mFloatingButton);
        }
    }
}

 

 

package com.XX.viewmotiontest02;

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.graphics.PixelFormat;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.util.Log;
import android.view.Gravity;
import android.view.WindowManager;
import android.widget.Button;

public class ViewMotionService extends Service {
    private static final String LOG_TAG = "ViewMotionService";
    Button mFloatingButton;
    WindowManager.LayoutParams mLayoutParams;
    WindowManager mWindowManager;

    @Override
    public void onCreate() {
        super.onCreate();

        Log.d(LOG_TAG, "onCreate" );
        mFloatingButton = new Button(this);
        mFloatingButton.setText("Button");
        mLayoutParams = new WindowManager.LayoutParams(WindowManager.LayoutParams.WRAP_CONTENT, WindowManager.LayoutParams.WRAP_CONTENT,
                WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY , 0, PixelFormat.TRANSPARENT); // w, h, type, flags, format;
        //mLayoutParams = new WindowManager.LayoutParams();
        //mLayoutParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
        //mLayoutParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
        //mLayoutParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY;
        mLayoutParams.flags = WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL
                | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED;
        //mLayoutParams.format = PixelFormat.TRANSPARENT;
        mLayoutParams.gravity = Gravity.LEFT | Gravity.TOP;
        mLayoutParams.x = 100;
        mLayoutParams.y = 300;
        mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
        //Log.d(LOG_TAG,"onCreate  - 2 change -3  ");
        mWindowManager.addView(mFloatingButton,mLayoutParams);
        //Log.d(LOG_TAG,"onCreate  - 3  ");
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.d(LOG_TAG, "onDestroy" );
        mWindowManager.removeView(mFloatingButton);
    }
}

 

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.xx.viewmotiontest02">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".ViewMotionTest02">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service android:name=".ViewMotionService" >
        </service>

    </application>

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

</manifest>

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