Question

在尝试将其更改为其他布局或更改屏幕方向时，我试图保存文本视图状态：

 @Override
public void onSaveInstanceState(Bundle outState) {
  super.onSaveInstanceState(outState);
  outState.putSerializable("GeneratedNumber", (Serializable) generatedNumber);//I get the error here

}

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
  super.onRestoreInstanceState(savedInstanceState);
  generatedNumber = (TextView) savedInstanceState.getSerializable("GeneratedNumber");

}

但是我得到一个错误

java.lang.ClassCastException：android.support.v7.widget.AppCompatTextView无法转换为java.io.Serializable

Also GeneratedNumber：是XML文件中的generatedNumber TextView ID。这是日志：

09-07 18：33：41.478 9406-9406 / maskedman.counter E / AndroidRuntime：FATAL EXCEPTION：main 进程：maskedman.counter，PID：9406 java.lang.ClassCastException：android.support.v7.widget.AppCompatTextView无法转换为java.io.Serializable 在maskedman.counter.CounterActivity.onSaveInstanceState（CounterActivity.java:34）在android.app.Activity.performSaveInstanceState（Activity.java:1474）在android.app.Instrumentation.callActivityOnSaveInstanceState（Instrumentation.java:1317）在android.app.ActivityThread.callCallActivityOnSaveInstanceState（ActivityThread.java:5393）在android.app.ActivityThread.performStopActivityInner（ActivityThread.java:4695）在android.app.ActivityThread.handleStopActivity（ActivityThread.java:4769）在android.app.ActivityThread.access $ 1400（ActivityThread.java:221）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1823）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:158）在android.app.ActivityThread.main（ActivityThread.java:7224）在java.lang.reflect.Method.invoke（本机方法）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:1230）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:1120）

有人可以帮助我吗？

Answer 1

问题是您尝试将文本视图存储为可序列化的，这是错误的。

检查此：

@Override
public void onSaveInstanceState(Bundle outState) {
  super.onSaveInstanceState(outState);
  // Save UI state changes to the savedInstanceState.
  // This bundle will be passed to onCreate if the process is
  // killed and restarted.
  savedInstanceState.putInt("GeneratedNumber", generatedNumber);// generatedNumber is integer
  // etc.
}

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
  super.onRestoreInstanceState(savedInstanceState);
  generatedNumber = savedInstanceState.getInt("GeneratedNumber");

}

/** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    /** 
*
*  layout initailization
*/
    if (savedInstanceState != null) {
       mTextView.setText(String.valueOf(generatedNumber));
    } 

  }

我希望这对您有用。

Answer 2

尝试仅将textview的值另存为字符串，然后将其再次放入onRestoreInstanceState

在onSaveInstanceState中尝试：

outState.putString("GeneratedNumber", yourTextView.getText().toString);

在onRestoreInstanceState中尝试：

String generatedNumber = savedInstanceState.getString("GeneratedNumber");
yourTextView.setText(generatedNumber);

无法将TextView强制转换为java.io.Serializable

2 个答案: