Question

考虑下面的mCreate等，int变量是动态增加的mCreate++ @Override public void onSaveInstanceState(Bundle savedInstanceState) { savedInstanceState.putInt(CREATE_KEY, mCreate); savedInstanceState.putInt( RESTART_KEY, mRestart); savedInstanceState.putInt(START_KEY, mStart); savedInstanceState.putInt(RESUME_KEY, mResume); super.onSaveInstanceState(savedInstanceState); } //////////// get if (savedInstanceState != null) { mCreate = savedInstanceState.getInt(CREATE_KEY, mCreate); mRestart = savedInstanceState.getInt( RESTART_KEY, mRestart); mStart = savedInstanceState.getInt(START_KEY, mStart); mResume = savedInstanceState.getInt(RESUME_KEY, mResume); }。我需要存储和检索他们最新的递增值。我认为我做得对，但有些人如何不应用最新的递增值。

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Answer 1

代码应该是这样的：

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

    savedInstanceState.putInt(CREATE_KEY, mCreate);
    savedInstanceState.putInt(RESTART_KEY, mRestart);
    savedInstanceState.putInt(START_KEY, mStart);
    savedInstanceState.putInt(RESUME_KEY, mResume);    
 }

 if (savedInstanceState != null) {
    mCreate = savedInstanceState.getInt(CREATE_KEY);
    mRestart = savedInstanceState.getInt(RESTART_KEY);
    mStart = savedInstanceState.getInt(START_KEY);
    mResume = savedInstanceState.getInt(RESUME_KEY);
 }

Answer 2

你想要这个。

private TextView mTvCreate;
private TextView mTvStart;
private TextView mTvResume;
private TextView mTvRestart;

private int mCreate = 0;
private int mStart = 0;
private int mResume = 0;
private int mRestart = 0;
// TODO: Create variables for each of the TextViews, called
    // mTvCreate, etc. 

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_one);

    // TODO: Assign the appropriate TextViews to the TextView variables
    // Hint: Access the TextView by calling Activity's findViewById()
    // textView1 = (TextView) findViewById(R.id.textView1);
    mTvCreate = (TextView) findViewById(R.id.create);
    mTvStart = (TextView) findViewById(R.id.start);
    mTvResume = (TextView) findViewById(R.id.resume);
    mTvRestart = (TextView) findViewById(R.id.restart);




    Button launchActivityTwoButton = (Button) findViewById(R.id.bLaunchActivityTwo); 
    launchActivityTwoButton.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO:
            // Launch Activity Two
            // Hint: use Context's startActivity() method

            // Create an intent stating which Activity you would like to start


            // Launch the Activity using the intent
            Intent startActivity = new Intent(ActivityOne.this, ActivityTwo.class);
            startActivity(startActivity);


        }
    });

    // Check for previously saved state
    if (savedInstanceState != null) {

        // TODO:
        // Restore value of counters from saved state
        // Only need 4 lines of code, one for every count variable
        mCreate = savedInstanceState.getInt(CREATE_KEY);
        mStart = savedInstanceState.getInt(START_KEY);
        mResume = savedInstanceState.getInt(RESUME_KEY);
        mRestart = savedInstanceState.getInt(RESTART_KEY);

    }

    ++mCreate;
    // TODO: Emit LogCat message
    Log.i(TAG, "onCreate() "+mCreate);
    displayCounts();

    // TODO:
    // Update the appropriate count variable
    // Update the user interface via the displayCounts() method



}

// Lifecycle callback overrides

@Override
public void onStart() {
    super.onStart();

    // TODO: Emit LogCat message
    ++mStart;
    Log.i(TAG, "onStart() "+mStart);
    // TODO:
    // Update the appropriate count variable
    // Update the user interface
    displayCounts();

}

@Override
public void onResume() {
    super.onResume();

    // TODO: Emit LogCat message

    ++mResume;
    Log.i(TAG, "onResume() "+mResume);
    // TODO:
    // Update the appropriate count variable
    // Update the user interface
    displayCounts();

}

@Override
public void onPause() {
    super.onPause();

    // TODO: Emit LogCat message

}

@Override
public void onStop() {
    super.onStop();

    // TODO: Emit LogCat message

}

@Override
public void onRestart() {
    super.onRestart();

    // TODO: Emit LogCat message

    ++mRestart;

    // TODO:
    // Update the appropriate count variable
    // Update the user interface
    Log.i(TAG, "onRestart() "+mRestart);
    displayCounts();

}

@Override
public void onDestroy() {
    super.onDestroy();

    // TODO: Emit LogCat message


}

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
                 super.onSaveInstanceState(savedInstanceState);
    // TODO:
    // Save state information with a collection of key-value pairs
    // 4 lines of code, one for every count variable
    savedInstanceState.putInt(CREATE_KEY, mCreate);
    savedInstanceState.putInt(START_KEY, mStart);
    savedInstanceState.putInt(RESUME_KEY, mResume);
    savedInstanceState.putInt(RESTART_KEY, mRestart);






}

// Updates the displayed counters
public void displayCounts() {

    mTvCreate.setText("onCreate() calls: " + mCreate);
    mTvStart.setText("onStart() calls: " + mStart);
    mTvResume.setText("onResume() calls: " + mResume);
    mTvRestart.setText("onRestart() calls: " + mRestart);

}

在onSavedInstanceState中存储和检索存储数据的问题（bundle savedInstanceState）

2 个答案: