Android Settings和SettingsProvider源码分析与修改

Setting显示开发者选项的逻辑

默认User版本没有“开发者选项”，我们可以通过点击版本号7次来显示开发者模式，今天来看下代码中是如何处理的：

首先是packages/apps/Settings/src/com/android/settings/Settings.java的初始化处理：

布尔值showDev是否默认显示“开发者选项”：

final boolean showDev = mDevelopmentPreferences.getBoolean(

DevelopmentSettings.PREF_SHOW,

android.os.Build.TYPE.equals(“eng”));

如果想让开发者选项默认显示，不需要点击7次版本号，可直接将showDev置为true即可：

final boolean showDev = true;

如果showDev为false，则在如下代码中隐藏“开发者选项”：

if (id == R.id.development_settings) {

if (!showDev) {

target.remove(i);

}

}

下面看一下点击版本号显示开发者选项的部分：

代码路径：packages/apps/Settings/src/com/android/settings/DeviceInfoSettings.java

首先是定义点击次数：

static final int TAPS_TO_BE_A_DEVELOPER = 7;

点击版本号的处理逻辑，若mDevHitCountdown小于0，则表示”开发者选项“已经显示，参考Resume函数的处理：

if (preference.getKey().equals(KEY_BUILD_NUMBER)) {

// Don’t enable developer options for secondary users.

if (UserHandle.myUserId() != UserHandle.USER_OWNER) return true;

if (mDevHitCountdown > 0) {

if (mDevHitCountdown == 1) {

if (super.ensurePinRestrictedPreference(preference)) {

return true;

}

}

mDevHitCountdown–;

if (mDevHitCountdown == 0) {

getActivity().getSharedPreferences(DevelopmentSettings.PREF_FILE,

Context.MODE_PRIVATE).edit().putBoolean(

DevelopmentSettings.PREF_SHOW, true).apply();

if (mDevHitToast != null) {

mDevHitToast.cancel();

}

mDevHitToast = Toast.makeText(getActivity(), R.string.show_dev_on,

Toast.LENGTH_LONG);

mDevHitToast.show();

} else if (mDevHitCountdown > 0

&& mDevHitCountdown < (TAPS_TO_BE_A_DEVELOPER-2)) {

if (mDevHitToast != null) {

mDevHitToast.cancel();

}

mDevHitToast = Toast.makeText(getActivity(), getResources().getQuantityString(

R.plurals.show_dev_countdown, mDevHitCountdown, mDevHitCountdown),

Toast.LENGTH_SHORT);

mDevHitToast.show();

}

} else if (mDevHitCountdown < 0) {

if (mDevHitToast != null) {

mDevHitToast.cancel();

}

mDevHitToast = Toast.makeText(getActivity(), R.string.show_dev_already,

Toast.LENGTH_LONG);

mDevHitToast.show();

}

}

Resume函数：

@Override

public void onResume() {

super.onResume();

PreferenceGroup parentPreference = getPreferenceScreen();

mDevHitCountdown = getActivity().getSharedPreferences(DevelopmentSettings.PREF_FILE,

Context.MODE_PRIVATE).getBoolean(