安卓7.1默认显示大小

设置–显示–显示大小调节
packages/apps/Settings/src/com/android/settings/display/ScreenZoomSettings.java +48

*/
public class ScreenZoomSettings extends PreviewSeekBarPreferenceFragment implements Indexable {

private int mDefaultDensity;
private int[] mValues;

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    mActivityLayoutResId = R.layout.screen_zoom_activity;

    // This should be replaced once the final preview sample screen is in place.
    mPreviewSampleResIds = new int[]{R.layout.screen_zoom_preview_1,
            R.layout.screen_zoom_preview_2,
            R.layout.screen_zoom_preview_settings};

    final DisplayDensityUtils density = new DisplayDensityUtils(getContext());

    final int initialIndex = density.getCurrentIndex();  这里打印实际的值，把该值写进framework默认
    if (initialIndex < 0) {
        // Failed to obtain default density, which means we failed to
        // connect to the window manager service. Just use the current
        // density and don't let the user change anything.
        final int densityDpi = getResources().getDisplayMetrics().densityDpi;
        mValues = new int[] { densityDpi };

frameworks/base/packages/SettingsLib/src/com/android/settingslib/display/DisplayDensityUtils.java +240
public static void setForcedDisplayDensity(final int displayId, final int density) {
final int userId = UserHandle.myUserId();
AsyncTask.execute(() -> {
try {
final IWindowManager wm = WindowManagerGlobal.getWindowManagerService();
wm.setForcedDisplayDensityForUser(displayId, density, userId);
} catch (RemoteException exc) {
Log.w(LOG_TAG, “Unable to save forced display density setting”);
}
});
}
}
frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.java +9870
@Override
public void setForcedDisplayDensityForUser(int displayId, int density, int userId) {
if (mContext.checkCallingOrSelfPermission(
android.Manifest.permission.WRITE_SECURE_SETTINGS) !=
PackageManager.PERMISSION_GRANTED) {
throw new SecurityException("Must hold permission " +
android.Manifest.permission.WRITE_SECURE_SETTINGS);
}
if (displayId != Display.DEFAULT_DISPLAY) {
throw new IllegalArgumentException(“Can only set the default display”);
}

    final int targetUserId = ActivityManager.handleIncomingUser(Binder.getCallingPid(),
            Binder.getCallingUid(), userId, false, true, "setForcedDisplayDensityForUser",
            null);
    final long ident = Binder.clearCallingIdentity();
    try {
        synchronized(mWindowMap) {
            final DisplayContent displayContent = getDisplayContentLocked(displayId);
            if (displayContent != null && mCurrentUserId == targetUserId) {
                setForcedDisplayDensityLocked(displayContent, density);
            }
            Settings.Secure.putStringForUser(mContext.getContentResolver(),
                    Settings.Secure.DISPLAY_DENSITY_FORCED,
                    Integer.toString(density), targetUserId);
        }
    } finally {
        Binder.restoreCallingIdentity(ident);
    }
}

Index: frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.java
===================================================================
--- frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.java    (revision 311)
+++ frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.java    (working copy)
@@ -7433,6 +7433,7 @@
                 + " from " + mRotation + (mAltOrientation ? " (alt)" : "")
                 + ", lastOrientation=" + mLastOrientation);
         }
+        rotation = Surface.ROTATION_0;
         mRotation = rotation;
         mAltOrientation = altOrientation;
@@ -9935,16 +9936,17 @@
     private int getForcedDisplayDensityForUserLocked(int userId) {
         String densityStr = Settings.Secure.getStringForUser(mContext.getContentResolver(),
                 Settings.Secure.DISPLAY_DENSITY_FORCED, userId);
+       Log.i("fan","get DISPLAY_DENSITY_FORCED="+densityStr);
         if (densityStr == null || densityStr.length() == 0) {
             densityStr = SystemProperties.get(DENSITY_OVERRIDE, null);
         }
         if (densityStr != null && densityStr.length() > 0) {
             try {
-                return Integer.parseInt(densityStr);
+    return 212;//Integer.parseInt(densityStr);        默认
             } catch (NumberFormatException ex) {
             }
         }
-        return 0;
+        return 212; 默认
     }