你好，下面是我的源代码；
这是 ActiviyOne.java
package course.labs.activitylab;
import android.app.Activity;
import android.app.Fragment;
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 ActivityOne
extends Activity {
// Use these as keys when you're saving state between reconfigurations
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-ActivityOne";
// Lifecycle counters
// TODO:
public Integer mCreate = 0;
public Integer mRestart = 0;
public Integer mStart = 0;
public Integer mResume = 0;
// Create variables named
// mCreate, mRestart, mStart and mResume
// to count calls to onCreate(), onRestart(), onStart() and
// onResume(). These variables should not be defined as static.
// You will need to increment these variables' values when their
// corresponding lifecycle methods get called.
// TODO: Create variables for each of the TextViews
TextView mTvCreate;
TextView mTvRestart;
TextView mTvStart;
TextView mTvResume;
// named mTvCreate, mTvRestart, mTvStart, mTvResume.
// for displaying the current count of each counter variable
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_one);
// TODO: Assign the appropriate TextViews to the TextView variables
mTvCreate = (TextView) findViewById(R.id.create);
mTvRestart = (TextView) findViewById(R.id.restart);
mTvResume = (TextView) findViewById(R.id.resume);
mTvStart = (TextView) findViewById(R.id.start);
// Hint: Access the TextView by calling Activity's findViewById()
// textView1 = (TextView) findViewById(R.id.textView1);
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
//Intent intent = null;
Intent StartIntent = new Intent(getApplicationContext(), ActivityTwo.class);
startActivity(StartIntent);
// Launch the Activity using the intent
}
});
// Has previous state been saved?
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);
mRestart = savedInstanceState.getInt(RESTART_KEY);
mResume = savedInstanceState.getInt(RESUME_KEY);
//Log.i(TAG, "mCreate " + mCreate + "mResume " + mResume + "mStart " + mStart + "mRestart " + mRestart);
//super.onSaveInstanceState(savedInstanceState);
}
// Emit LogCat message
Log.i(TAG, "Entered the onCreate() method");
// TODO:
mCreate++;
displayCounts();
// Update the appropriate count variable
// Update the user interface via the displayCounts() method
}
// Lifecycle callback overrides
@Override
public void onStart() {
super.onStart();
// Emit LogCat message
Log.i(TAG, "Entered the onStart() method");
// TODO:
mStart++;
displayCounts();
// Update the appropriate count variable
// Update the user interface
}
@Override
public void onResume() {
super.onResume();
// Emit LogCat message
Log.i(TAG, "Entered the onResume() method");
// TODO:
mResume++;
displayCounts();
// Update the appropriate count variable
// Update the user interface
}
@Override
public void onPause() {
super.onPause();
// Emit LogCat message
Log.i(TAG, "Entered the onPause() method");
}
@Override
public void onStop() {
super.onStop();
// Emit LogCat message
Log.i(TAG, "Entered the onStop() method");
}
@Override
public void onRestart() {
super.onRestart();
// Emit LogCat message
Log.i(TAG, "Entered the onRestart() method");
// TODO:
mRestart++;
displayCounts();
// Update the appropriate count variable
// Update the user interface
}
@Override
public void onDestroy() {
super.onDestroy();
// Emit LogCat message
Log.i(TAG, "Entered the onDestroy() method");
}
@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
// TODO:
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putInt(CREATE_KEY, mCreate);
savedInstanceState.putInt(RESTART_KEY, mRestart);
savedInstanceState.putInt(RESUME_KEY, mResume);
savedInstanceState.putInt(START_KEY, mStart);
// Save state information with a collection of key-value pairs
// 4 lines of code, one for every count variable
}
// Updates the displayed counters
// This method expects that the counters and TextView variables use the
// names
// specified above
public void displayCounts() {
// TODO - uncomment these lines
mTvCreate.setText("onCreate() calls: " + mCreate);
mTvStart.setText("onStart() calls: " + mStart);
mTvResume.setText("onResume() calls: " + mResume);
mTvRestart.setText("onRestart() calls: " + mRestart);
}
}
这是ActivityTwo.java
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 {
// Use these as keys when you're saving state between reconfigurations
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:
public Integer mCreate = 0;
public Integer mRestart = 0;
public Integer mStart = 0;
public Integer mResume = 0;
// Create variables named
// mCreate, mRestart, mStart and mResume
// to count calls to onCreate(), onRestart(), onStart() and
// onResume(). These variables should not be defined as static.
// You will need to increment these variables' values when their
// corresponding lifecycle methods get called.
// TODO: Create variables for each of the TextViews
TextView mTvCreate;
TextView mTvRestart;
TextView mTvStart;
TextView mTvResume;
// named mTvCreate, mTvRestart, mTvStart, mTvResume.
// for displaying the current count of each counter variable
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_two);
// TODO: Assign the appropriate TextViews to the TextView variables
mTvCreate = (TextView) findViewById(R.id.create);
mTvRestart = (TextView) findViewById(R.id.restart);
mTvStart = (TextView) findViewById(R.id.start);
mTvResume = (TextView) findViewById(R.id.resume);
// Hint: Access the TextView by calling Activity's findViewById()
// textView1 = (TextView) findViewById(R.id.textView1);
Button closeButton = (Button) findViewById(R.id.bClose);
closeButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO:
/*
Intent FinishIntent = new Intent(ActivityTwo.this, ActivityOne.class);
finish();
*/
// This function closes Activity Two
// Hint: use Context's finish() method
// ActivityTwo.this.finish();
// finish();
// Intent tmpIntent = new Intent(getApplicationContext(), ActivityOne.class);
finish();
//ActivityTwo.this.finish();
}
});
/*
savedInstanceState.putInt(CREATE_KEY, mCreate);
savedInstanceState.putInt(RESTART_KEY, mRestart);
savedInstanceState.putInt(RESUME_KEY, mResume);
savedInstanceState.putInt(START_KEY, mStart);
*/
// Has previous state been saved?
if(savedInstanceState != null) {
// TODO:
// Log.i(TAG, "Entered restoring values of counters");
super.onRestoreInstanceState(savedInstanceState);
mCreate = savedInstanceState.getInt(CREATE_KEY);
mStart = savedInstanceState.getInt(START_KEY);
mRestart = savedInstanceState.getInt(RESTART_KEY);
mResume = savedInstanceState.getInt(RESUME_KEY);
//Log.i(TAG, "mCreate " + mCreate + "mResume " + mResume + "mStart " + mStart + "mRestart " + mRestart);
// Restore value of counters from saved state
// Only need 4 lines of code, one for every count variable
// super.onSaveInstanceState(savedInstanceState);
}
// Emit LogCat message
mCreate++;
Log.i(TAG, "Entered the onCreate() method");
// TODO:
displayCounts();
// Update the appropriate count variable
// Update the user interface via the displayCounts() method
}
// Lifecycle callback methods overrides
@Override
public void onStart() {
super.onStart();
// Emit LogCat message
mStart++;
Log.i(TAG, "Entered the onStart() method");
// TODO:
displayCounts();
// Update the appropriate count variable
// Update the user interface
}
@Override
public void onResume() {
super.onResume();
// Emit LogCat message
mResume++;
Log.i(TAG, "Entered the onResume() method");
// TODO:
displayCounts();
// Update the appropriate count variable
// Update the user interface
}
@Override
public void onPause() {
super.onPause();
// Emit LogCat message
Log.i(TAG, "Entered the onPause() method");
}
@Override
public void onStop() {
super.onStop();
// Emit LogCat message
Log.i(TAG, "Entered the onStop() method");
}
@Override
public void onRestart() {
super.onRestart();
// Emit LogCat message
mRestart++;
Log.i(TAG, "Entered the onRestart() method");
// TODO:
displayCounts();
// Update the appropriate count variable
// Update the user interface
}
@Override
public void onDestroy() {
super.onDestroy();
// Emit LogCat message
Log.i(TAG, "Entered the onDestroy() 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
Log.i(TAG, "Saving instance state");
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putInt(CREATE_KEY, mCreate);
savedInstanceState.putInt(RESTART_KEY, mRestart);
savedInstanceState.putInt(RESUME_KEY, mResume);
savedInstanceState.putInt(START_KEY, mStart);
}
// Updates the displayed counters
// This method expects that the counters and TextView variables use the
// names
// specified above
public void displayCounts() {
// TODO - uncomment these lines
mTvCreate.setText("onCreate() calls: " + mCreate);
mTvStart.setText("onStart() calls: " + mStart);
mTvResume.setText("onResume() calls: " + mResume);
mTvRestart.setText("onRestart() calls: " + mRestart);
}
}
我有一个问题。当我运行程序时，我想计算我调用了多少次
onCreate(), onStart(), onResume(), onResume() 它适用于 Activity 一
，但在 Activity 2 中不起作用。计数器不起作用。
谢谢
最佳答案
1) Activity1 状态保存在堆栈上 -> 当你调用 Activity2 时。
2)当点击返回时，Activity2状态被保存然后被销毁(从堆栈中移除)。
3) Activity1 从堆栈中读取保存的状态。
试试这个 [ Activity 1]:
launchActivityTwoButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent StartIntent = new Intent(getApplicationContext(), ActivityTwo.class);
StartIntent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(StartIntent);
}
});
[ Activity 二]:
closeButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent intent= new Intent(getApplicationContext(), ActivityOne.class);
intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(intent);
}
});
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