android双屏之副屏待机显示图片
摘要：android原生有双屏的机制，但需要芯片厂商适配框架后在底层实现。本文在基于芯发8766已实现底层适配的基础上，仅针对上层Launcher部分对系统进行改造，从而实现在开机后副屏显示一张待机图片。
副屏布局
由于仅显示一张图片，故布局仅需填充ImageView
Index: vendor/mediatek/proprietary/packages/apps/Launcher3/res/layout/presentation_image.xml
===================================================================
--- vendor/mediatek/proprietary/packages/apps/Launcher3/res/layout/presentation_image.xml (不存在的)
+++ vendor/mediatek/proprietary/packages/apps/Launcher3/res/layout/presentation_image.xml (版本 1687)
@@ -0,0 +1,6 @@
+<ImageView
+ xmlns:android="http://schemas.android.com/apk/res/android"
+ android:id="@+id/image_view"
+ android:layout_width="match_parent"
+ android:layout_height="match_parent"
+ android:scaleType="centerInside" />
关于android:scaleType的详细说明和用法，可参考官网API
或者以下BLOG：
Android的ImageView scaleType八大属性，你都了解吗？
android学习笔记之ImageView的scaleType属性
准备一张符合副屏分辨率的图片
博主所使用的副屏为320x240，图片格式为JPG
Index: vendor/mediatek/proprietary/packages/apps/Launcher3/res/mipmap-hdpi/presents.jpg
副屏图片管理类
新增图换图片功能，在显示以上图片的基础上，如果所指定路径有替换的图片文件，则使用替换的图片文件。
Index: vendor/mediatek/proprietary/packages/apps/Launcher3/src/com/android/launcher3/presentation/ImagePresentation.java
===================================================================
--- vendor/mediatek/proprietary/packages/apps/Launcher3/src/com/android/launcher3/presentation/ImagePresentation.java (不存在的)
+++ vendor/mediatek/proprietary/packages/apps/Launcher3/src/com/android/launcher3/presentation/ImagePresentation.java (版本 1687)
@@ -0,0 +1,48 @@
+package com.android.launcher3.presentation;
+
+import android.app.Presentation;
+import android.content.Context;
+import android.graphics.ColorMatrix;
+import android.graphics.ColorMatrixColorFilter;
+import android.net.Uri;
+import android.os.Bundle;
+import android.os.Environment;
+import android.util.Log;
+import android.view.Display;
+import android.widget.ImageView;
+
+import com.android.launcher3.R;
+
+import java.io.File;
+
+public class ImagePresentation extends Presentation {
+ private static final String TAG = "ImagePresentation";
+
+ ImageView imageView;
+
+ public ImagePresentation(Context context, Display display) {
+ super(context, display);
+ }
+
+ @Override
+ protected void onCreate(Bundle savedInstanceState) {
+ super.onCreate(savedInstanceState);
+ setContentView(R.layout.presentation_image);
+
+ imageView = findViewById(R.id.image_view);
+ imageView.setImageResource(R.mipmap.presents);
+ }
+
+ @Override
+ protected void onStart() {
+ super.onStart();
+ String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/presents_replace.jpg";
+ File imageFile = new File(path);
+ if (imageFile.exists()) {
+ imageView.setImageURI(Uri.fromFile(new File(path)));
+ } else {
+ Log.d(TAG, "The replacement image does not exist, use the original image");
+ }
+ }
+}在Launcher部分的实现
由于需要开机后显示待机的图片，并且副屏的内容默认是投射填充主屏的内容，故开机后会有准备阶段，主要显示一部分Launcher的内容，在完全准备好后，再显示副屏的待机图片。
Index: vendor/mediatek/proprietary/packages/apps/Launcher3/src/com/android/launcher3/Launcher.java
===================================================================
--- vendor/mediatek/proprietary/packages/apps/Launcher3/src/com/android/launcher3/Launcher.java (版本 1678)
+++ vendor/mediatek/proprietary/packages/apps/Launcher3/src/com/android/launcher3/Launcher.java (版本 1687)
@@ -70,6 +70,7 @@import android.app.NotificationChannel;import android.app.NotificationManager;import android.app.PendingIntent;
+import android.app.Presentation;import android.appwidget.AppWidgetHostView;import android.appwidget.AppWidgetManager;import android.content.ActivityNotFoundException;
@@ -86,6 +87,7 @@import android.graphics.Bitmap;import android.graphics.Rect;import android.graphics.RectF;
+import android.hardware.display.DisplayManager;import android.os.Build;import android.os.Bundle;import android.os.CancellationSignal;
@@ -99,6 +101,7 @@import android.text.method.TextKeyListener;import android.util.Log;import android.util.SparseArray;
+import android.view.Display;import android.view.KeyEvent;import android.view.KeyboardShortcutGroup;import android.view.KeyboardShortcutInfo;
@@ -168,6 +171,7 @@import com.android.launcher3.popup.PopupContainerWithArrow;import com.android.launcher3.popup.PopupDataProvider;import com.android.launcher3.popup.SystemShortcut;
+import com.android.launcher3.presentation.ImagePresentation;import com.android.launcher3.qsb.QsbContainerView;import com.android.launcher3.statemanager.StateManager;import com.android.launcher3.statemanager.StateManager.StateHandler;
@@ -387,6 +391,11 @@private StringCache mStringCache;+ // @ + {
+ private DisplayManager mDisplayManager;
+ private Presentation secondaryPresentation;
+ // @ + }
+@Override@TargetApi(Build.VERSION_CODES.S)protected void onCreate(Bundle savedInstanceState) {
@@ -453,6 +462,34 @@super.onCreate(savedInstanceState);+ // @ + {
+ mDisplayManager = (DisplayManager) getSystemService(Context.DISPLAY_SERVICE);
+ mDisplayManager.registerDisplayListener(new DisplayManager.DisplayListener() {
+ @Override
+ public void onDisplayAdded(int displayId) {
+ Log.d(TAG, "onDisplayAdded");
+ }
+
+ @Override
+ public void onDisplayRemoved(int displayId) {
+ Log.d(TAG, "onDisplayRemoved");
+ }
+
+ @Override
+ public void onDisplayChanged(int displayId) {}
+ }, null);
+
+ Display[] displays = mDisplayManager.getDisplays();
+ for (Display display : displays) {
+ if (display.getDisplayId() != Display.DEFAULT_DISPLAY) {
+ secondaryPresentation = new ImagePresentation(this, display);
+ //secondaryPresentation = new VideoPresentation(this, display);
+ secondaryPresentation.show();
+ break;
+ }
+ }
+ // @ + }
+LauncherAppState app = LauncherAppState.getInstance(this);mOldConfig = new Configuration(getResources().getConfiguration());mModel = app.getModel();
@@ -1718,6 +1755,12 @@mOverlayManager.onActivityDestroyed(this);mUserChangedCallbackCloseable.close();
+
+ // @ + {
+ if (secondaryPresentation != null && secondaryPresentation.isShowing()) {
+ secondaryPresentation.dismiss();
+ }
+ // @ + }}public LauncherAccessibilityDelegate getAccessibilityDelegate() {扩展 —— 副屏视频布局
能显示图片，自然也能播放视频
Index: vendor/mediatek/proprietary/packages/apps/Launcher3/res/layout/presentation_video.xml
===================================================================
--- vendor/mediatek/proprietary/packages/apps/Launcher3/res/layout/presentation_video.xml (不存在的)
+++ vendor/mediatek/proprietary/packages/apps/Launcher3/res/layout/presentation_video.xml (版本 1687)
@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<VideoView
+ xmlns:android="http://schemas.android.com/apk/res/android"
+ android:id="@+id/video_view"
+ android:layout_width="match_parent"
+ android:layout_height="match_parent"
+ android:scaleType="centerCrop" />准备一段符合副屏分辨率的视频
博主所使用的副屏为320x240，视频格式为MP4
Index: vendor/mediatek/proprietary/packages/apps/Launcher3/res/raw/video_320_240.mp4
副屏视频管理类
播放的视频内容需要根据副屏的比例进行缩放，并且根据实际情况实现循环播放。
Index: vendor/mediatek/proprietary/packages/apps/Launcher3/src/com/android/launcher3/presentation/VideoPresentation.java
===================================================================
--- vendor/mediatek/proprietary/packages/apps/Launcher3/src/com/android/launcher3/presentation/VideoPresentation.java (不存在的)
+++ vendor/mediatek/proprietary/packages/apps/Launcher3/src/com/android/launcher3/presentation/VideoPresentation.java (版本 1687)
@@ -0,0 +1,68 @@
+package com.android.launcher3.presentation;
+
+import android.app.Presentation;
+import android.content.Context;
+import android.graphics.Point;
+import android.net.Uri;
+import android.os.Bundle;
+import android.util.Log;
+import android.view.Display;
+import android.view.ViewGroup;
+import android.widget.VideoView;
+
+import com.android.launcher3.R;
+
+public class VideoPresentation extends Presentation {
+ private static final String TAG = "VideoPresentation";
+ private VideoView videoView;
+
+ public VideoPresentation(Context context, Display display) {
+ super(context, display);
+ }
+
+ @Override
+ protected void onCreate(Bundle savedInstanceState) {
+ super.onCreate(savedInstanceState);
+ setContentView(R.layout.presentation_video);
+ videoView = findViewById(R.id.video_view);
+
+ Uri videoUri = Uri.parse("android.resource://" + getContext().getPackageName() + "/" + R.raw.video_320_240);
+ videoView.setVideoURI(videoUri);
+
+ videoView.setOnPreparedListener(mp -> {
+ int videoWidth = mp.getVideoWidth();
+ int videoHeight = mp.getVideoHeight();
+
+ Point screenSize = new Point();
+ getDisplay().getRealSize(screenSize);
+ int screenWidth = screenSize.x;
+ int screenHeight = screenSize.y;
+
+ float widthRatio = (float) screenWidth / videoWidth;
+ float heightRatio = (float) screenHeight / videoHeight;
+ float scale = Math.min(widthRatio, heightRatio);
+
+ ViewGroup.LayoutParams params = videoView.getLayoutParams();
+ params.width = (int) (videoWidth * scale);
+ params.height = (int) (videoHeight * scale);
+ videoView.setLayoutParams(params);
+ });
+
+ videoView.setOnCompletionListener(mp -> {
+ videoView.start(); // replay
+ });
+
+
+
+ videoView.start();
+ }
+
+ @Override
+ protected void onStop() {
+ super.onStop();
+ if (videoView != null) {
+ videoView.stopPlayback();
+ }
+ }
+}
+