深海游弋的鱼 – 默默的点滴

最近遇到一个应用崩溃问题，这个问题是由于在 Activity 的 onSaveInstanceState 中进行了数据的保存，然后在 onRestoreInstanceState 进行解析的时候出现崩溃。

实际测试的时候，发现当内存充足的时候，非常难稳定的诱发 Activity 的 onSaveInstanceState 事件。

早期的版本，可以通过 ActivityManagerNative.getDefault().setAlwaysFinish 来强制系统在 Activity 切换到后台之后，立即触发 onSaveInstanceState 。

参考代码如下：

// Updates the system Always Finish setting
private void writeFinishOptions()
{
    try
    {
        // Due to restrictions related to hidden APIs, need to emulate the line below
        // using reflection:
        // ActivityManagerNative.getDefault().setAlwaysFinish(mAlwaysFinish);
        final Class   classActivityManagerNative = Class.forName("android.app.ActivityManagerNative");
        final Method     methodGetDefault = classActivityManagerNative.getMethod("getDefault");
        final Method     methodSetAlwaysFinish = classActivityManagerNative.getMethod("setAlwaysFinish", new Class[] {boolean.class});
        final Object     objectInstance = methodGetDefault.invoke(null);
        methodSetAlwaysFinish.invoke(objectInstance, new Object[]{mAlwaysFinish});
    }
    catch (Exception ex)
    {
        showAlert("Could not set always finish:\n\n" + ex, "Error");
    }
}
 
// Gets the latest AlwaysFinish value from the system and
// updates the checkbox
private void updateFinishOptions()
{
    mAlwaysFinish = Settings.System.getInt(getContentResolver(), Settings.System.ALWAYS_FINISH_ACTIVITIES, 0) != 0;
    mAlwaysFinishCB.setChecked(mAlwaysFinish);
}

// Updates the system Always Finish setting

private void writeFinishOptions()

{

try

{

// Due to restrictions related to hidden APIs, need to emulate the line below

// using reflection:

// ActivityManagerNative.getDefault().setAlwaysFinish(mAlwaysFinish);

final Class classActivityManagerNative = Class.forName("android.app.ActivityManagerNative");

final Method methodGetDefault = classActivityManagerNative.getMethod("getDefault");

final Method methodSetAlwaysFinish = classActivityManagerNative.getMethod("setAlwaysFinish", new Class[] {boolean.class});

final Object objectInstance = methodGetDefault.invoke(null);

methodSetAlwaysFinish.invoke(objectInstance, new Object[]{mAlwaysFinish});

}

catch (Exception ex)

{

showAlert("Could not set always finish:\n\n" + ex, "Error");

}

// Gets the latest AlwaysFinish value from the system and

// updates the checkbox

private void updateFinishOptions()

{

mAlwaysFinish = Settings.System.getInt(getContentResolver(), Settings.System.ALWAYS_FINISH_ACTIVITIES, 0) != 0;

mAlwaysFinishCB.setChecked(mAlwaysFinish);

}

但是遗憾的是，新系统比如 Android 8 等系统上，在真机环境中已经没办法通过上述的方法进行诱发了。系统会直接抛出异常，或者设置无效。

真机环境，可以尝试在 开发人员选项 中设置开启 “不保留活动” 按钮，如下图所示：

对于编写单元测试用例的情况来说，建议使用 AndroidX 引入的 ActivityScenario 来进行测试，参考代码如下；

private boolean isEmulator() {
    final Context appContext = InstrumentationRegistry.getInstrumentation().getTargetContext();
    return ((TelephonyManager) appContext.getSystemService(Context.TELEPHONY_SERVICE))
                .getNetworkOperatorName().toLowerCase().equals("android");
}

// 此测试用例仅仅建议在Android模拟器中运行，真机调试的时候会在此代码中卡住
if (isEmulator()) {
    final ActivityScenario<SecKeyboardActivity> scenario = ActivityScenario.launch(Activity.class);
    scenario.moveToState(Lifecycle.State.CREATED);    // Moves the activity state to State.CREATED.
    
    // 诱发系统调用 onSaveInstanceState/onRestoreInstanceState
    scenario.recreate();
}

private boolean isEmulator() {

final Context appContext = InstrumentationRegistry.getInstrumentation().getTargetContext();

return ((TelephonyManager) appContext.getSystemService(Context.TELEPHONY_SERVICE))

.getNetworkOperatorName().toLowerCase().equals("android");

}

// 此测试用例仅仅建议在Android模拟器中运行，真机调试的时候会在此代码中卡住

if (isEmulator()) {

final ActivityScenario<SecKeyboardActivity> scenario = ActivityScenario.launch(Activity.class);

scenario.moveToState(Lifecycle.State.CREATED); // Moves the activity state to State.CREATED.

// 诱发系统调用 onSaveInstanceState/onRestoreInstanceState

scenario.recreate();

}

目前测试发现，在真机上执行上述测试用例（Android 10），会在 ActivityScenario.launch(Activity.class); 的时候抛出超时异常，目前真机暂时没解决方法，建议在模拟器上执行测试用例。

可能的崩溃日志如下：

10:54:42 V/InstrumentationResultParser: java.lang.AssertionError: Activity never becomes requested state "[RESUMED]" (last lifecycle transition = "STOPPED")
10:54:42 V/InstrumentationResultParser: at androidx.test.core.app.ActivityScenario.waitForActivityToBecomeAnyOf(ActivityScenario.java:228)
10:54:42 V/InstrumentationResultParser: at androidx.test.core.app.ActivityScenario.moveToState(ActivityScenario.java:368)
10:54:42 V/InstrumentationResultParser: at com.myapplication.android.test.HomeTest.launchActivity(HomeTest.java:30)
10:54:42 V/InstrumentationResultParser: at java.lang.reflect.Method.invoke(Native Method)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
10:54:42 V/InstrumentationResultParser: at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
10:54:42 V/InstrumentationResultParser: at androidx.test.internal.runner.junit4.statement.RunBefores.evaluate(RunBefores.java:76)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
10:54:42 V/InstrumentationResultParser: at androidx.test.ext.junit.runners.AndroidJUnit4.run(AndroidJUnit4.java:104)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.Suite.runChild(Suite.java:128)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.Suite.runChild(Suite.java:27)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
10:54:42 V/InstrumentationResultParser: at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
10:54:42 V/InstrumentationResultParser: at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
10:54:42 V/InstrumentationResultParser: at androidx.test.internal.runner.TestExecutor.execute(TestExecutor.java:56)
10:54:42 V/InstrumentationResultParser: at androidx.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:388)
10:54:42 V/InstrumentationResultParser: at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:2075)

10:54:42 V/InstrumentationResultParser: java.lang.AssertionError: Activity never becomes requested state "[RESUMED]" (last lifecycle transition = "STOPPED")

10:54:42 V/InstrumentationResultParser: at androidx.test.core.app.ActivityScenario.waitForActivityToBecomeAnyOf(ActivityScenario.java:228)

10:54:42 V/InstrumentationResultParser: at androidx.test.core.app.ActivityScenario.moveToState(ActivityScenario.java:368)

10:54:42 V/InstrumentationResultParser: at com.myapplication.android.test.HomeTest.launchActivity(HomeTest.java:30)

10:54:42 V/InstrumentationResultParser: at java.lang.reflect.Method.invoke(Native Method)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)

10:54:42 V/InstrumentationResultParser: at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)

10:54:42 V/InstrumentationResultParser: at androidx.test.internal.runner.junit4.statement.RunBefores.evaluate(RunBefores.java:76)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.run(ParentRunner.java:363)

10:54:42 V/InstrumentationResultParser: at androidx.test.ext.junit.runners.AndroidJUnit4.run(AndroidJUnit4.java:104)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.Suite.runChild(Suite.java:128)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.Suite.runChild(Suite.java:27)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)

10:54:42 V/InstrumentationResultParser: at org.junit.runners.ParentRunner.run(ParentRunner.java:363)

10:54:42 V/InstrumentationResultParser: at org.junit.runner.JUnitCore.run(JUnitCore.java:137)

10:54:42 V/InstrumentationResultParser: at org.junit.runner.JUnitCore.run(JUnitCore.java:115)

10:54:42 V/InstrumentationResultParser: at androidx.test.internal.runner.TestExecutor.execute(TestExecutor.java:56)

10:54:42 V/InstrumentationResultParser: at androidx.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:388)

10:54:42 V/InstrumentationResultParser: at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:2075)

测试Activity的onSaveInstanceState/onRestoreInstanceState

参考链接

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参考链接

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