Question

我有两个示例活动，一个名为activityone，另一个名为activitytwo

activitytwo只有一个按钮可以再次调用activityone，但是当显示activityone时，由于某种原因activitytwo始终保持onrestart()而不是停止

这是活动2的代码（活动1具有相同的代码）

package course.labs.activitylab;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log; 
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class ActivityTwo extends Activity {

private static final String RESTART_KEY = "restart";
private static final String RESUME_KEY = "resume";
private static final String START_KEY = "start";
private static final String CREATE_KEY = "create";

// String for LogCat documentation
private final static String TAG = "Lab-ActivityTwo";

// Lifecycle counters

// TODO:
// Create counter variables for onCreate(), onRestart(), onStart() and
// onResume(), called mCreate, etc.
// You will need to increment these variables' values when their
// corresponding lifecycle methods get called

private Integer mCreate = 0;
private Integer mRestart = 0;
private Integer mStart = 0;
private Integer mResume = 0;



// TODO: Create variables for each of the TextViews, called
    // mTvCreate, etc. 

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


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

    // 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);
    mTvRestart = (TextView) findViewById(R.id.restart);
    mTvStart = (TextView) findViewById(R.id.start);
    mTvResume = (TextView) findViewById(R.id.resume);





    Button closeButton = (Button) findViewById(R.id.bClose); 
    closeButton.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            // TODO:
            // This function closes Activity Two
            // Hint: use Context's finish() method
            //finish();
            Intent tmpIntent = new Intent(getApplicationContext(), ActivityOne.class);

            // Launch the Activity using the intent
            startActivity(tmpIntent);

        }
    });

    // 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



    }

    // TODO: Emit LogCat message
    Log.i(TAG, "Entered the onCreate() method");


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



}

// Lifecycle callback methods overrides

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

    // TODO: Emit LogCat message
    Log.i(TAG, "Entered the onStart() method");

    // TODO:
    // Update the appropriate count variable
    // Update the user interface
    mStart++;
    displayCounts();


}

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

    // TODO: Emit LogCat message
    Log.i(TAG, "Entered the onResume() method");

    // TODO:
    // Update the appropriate count variable
    // Update the user interface
    mResume++;
    displayCounts();



}

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

    // TODO: Emit LogCat message
    Log.i(TAG, "Entered the onPause() method");



}

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

    // TODO: Emit LogCat message
    Log.i(TAG, "Entered the onStop() method");


}

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

    // TODO: Emit LogCat message
    Log.i(TAG, "Entered the onRestart() method");

    // TODO:
    // Update the appropriate count variable
    // Update the user interface
    mRestart++;
    displayCounts();


}

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

    // TODO: Emit LogCat message
    Log.i(TAG, "Entered the onRestart() method");

}

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {

    // TODO:
    // Save counter state information with a collection of key-value pairs
    // 4 lines of code, one for every count variable






}

// 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);

    }
}

这是日志

//Enter to the app for first time
02-05 03:36:48.783: I/Lab-ActivityOne(1591): Entered the onCreate() method
02-05 03:36:48.783: I/Lab-ActivityOne(1591): Entered the onStart() method
02-05 03:36:48.783: I/Lab-ActivityOne(1591): Entered the onResume() method
//Click the start activity 2 button
02-05 03:36:58.413: I/Lab-ActivityOne(1591): Entered the onPause() method
02-05 03:36:58.713: I/Lab-ActivityTwo(1591): Entered the onCreate() method
02-05 03:36:58.733: I/Lab-ActivityTwo(1591): Entered the onStart() method
02-05 03:36:58.733: I/Lab-ActivityTwo(1591): Entered the onResume() method
02-05 03:36:59.093: I/Choreographer(1591): Skipped 46 frames!  The application may be doing too    much work on its main thread.
02-05 03:36:59.933: I/Lab-ActivityOne(1591): Entered the onStop() method
02-05 03:36:59.953: I/Lab-ActivityOne(1591): Entered the onDestroy() method
//Click Close Activity 2
02-05 03:37:06.923: I/Lab-ActivityTwo(1591): Entered the onPause() method
02-05 03:37:07.203: I/Lab-ActivityOne(1591): Entered the onCreate() method
02-05 03:37:07.203: I/Lab-ActivityOne(1591): Entered the onStart() method
02-05 03:37:07.223: I/Lab-ActivityOne(1591): Entered the onResume() method
02-05 03:37:07.623: I/Choreographer(1591): Skipped 68 frames!  The application may be doing too much work on its main thread.
02-05 03:37:08.513: I/Lab-ActivityTwo(1591): Entered the onStop() method
02-05 03:37:08.523: I/Lab-ActivityTwo(1591): Entered the onRestart() method

此时活动1再次显示，但活动2 onRestart而不是仅保持Stop（）因为不再可见？

Answer 1

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

// TODO: Emit LogCat message
Log.i(TAG, "Entered the onRestart() method");

您需要将其记录为onDestroy

Answer 2

如果要在单击关闭按钮时停止ActivityTwo，请使用完成（）。

Button closeButton = (Button) findViewById(R.id.bClose); 
closeButton.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {

    // TODO:
    // This function closes Activity Two
    // Hint: use Context's finish() method
    ActivityTwo.this.finish();
}

});

Answer 3

onDestroy（）方法的log.i中的错字。应该是“输入 onDestroy（）方法”

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

    // TODO: Emit LogCat message
    Log.i(TAG, "Entered the onDestroy() method");

}

Coursera是最好的！

Android Activity总是调用onRestart而不是停留在Stop

3 个答案: