如何将数据从活动 A 传递/保存到 B，然后再传递到 B？

Posted 2023-04-19

【中文标题】如何将数据从活动 A 传递/保存到 B，然后再传递到 B？

【英文标题】：How to pass/save the data from activity A to B and then to B?

【发布时间】：2015-03-16 02:11:55

【问题描述】：

我用 eclipse 制作了一个应用程序，它是关于按钮的，第一个按钮计算我所做的点击，第二个按钮将我发送到活动 B 和 .在活动 B 中，包括我制作的第三个按钮来购买 100 次点击。当我单击按钮购买 100 次时，我现在面临的问题是，单击 mainactivity 上的金额不是从 1000 次开始，并且不保存我在购买之前所做的最后一次单击。

主活动：

public class MainActivity extends ActionBarActivity 

int count = 0;
@Override
protected void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Button button2 = (Button) findViewById(R.id.button2);
    button2.setOnClickListener(new OnClickListener() 

        @Override
        public void onClick(View v) 
            // TODO Auto-generated method stub
            Intent intent = new Intent(getApplicationContext(),MainActivityTwo.class);

            startActivityForResult(intent, count);

        
    );



final Button button1 = (Button) findViewById(R.id.button1);

final TextView textView1 = (TextView) findViewById(R.id.textView1);

button1.setOnClickListener(new View.OnClickListener()



    @Override
    public void onClick(View v) 
        // TODO Auto-generated method stub
        Intent in = getIntent();
        int cou = in.getIntExtra("", 1000);
        // Get the extras (if there are any)
        Bundle extras = in.getExtras();
        if (extras != null) 

                // TODO: Do something with the value of isNew.
            count++;
            int sum = cou+ count;

            textView1.setText("Clicked "+ sum +":times");


             else
             count++;
             textView1.setText("Clicked"+ count +":times");
         
    
);

Activity_Two：

public class MainActivityTwo extends ActionBarActivity 


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

    Button btn = (Button) findViewById(R.id.btn);
    btn.setOnClickListener(new OnClickListener() 

        @Override
        public void onClick(View v) 
            // TODO Auto-generated method stub
            Intent i = new Intent(getApplicationContext(),MainActivity.class);
            i.putExtra("", 1000);

            startActivity(i);
        
    );

【问题讨论】：

你的 OnActivityForResult 方法在哪里也发布了

@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) // 检查 requestCode 是否对应你的 Second Activity。 if (requestCode == 0) // 检查结果是否正常 if (resultCode == RESULT_OK)

单击按钮时，您正在增加计数，但不会将其传递给下一个活动，并且还使用一些键名（如计数）而不是“”作为键名来在意图中添加值

【参考方案1】：

试试那个代码

更新 MainActivity

public class MainActivity extends Activity 

static int count = 0;
public static int MAIN_ACTIVITY = 1;

TextView textView1;
Button button1;
@Override
protected void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Button button2 = (Button) findViewById(R.id.button2);
    button2.setOnClickListener(new OnClickListener() 

        @Override
        public void onClick(View v) 
            // TODO Auto-generated method stub
            Intent intent = new Intent(getApplicationContext(),
                    MainActivityTwo.class);

            startActivityForResult(intent, MAIN_ACTIVITY);

        
    );

     button1 = (Button) findViewById(R.id.button1);

     textView1 = (TextView) findViewById(R.id.textView1);

    button1.setOnClickListener(new View.OnClickListener()

    

        @Override
        public void onClick(View v) 
            // TODO Auto-generated method stub

            count++;
            textView1.setText("total clicks are => "+count);


        
    );


@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) 
    if (requestCode == MAIN_ACTIVITY)  // Check if result is ok

        if (resultCode == RESULT_OK) 

            int clicks = data.getIntExtra("100_CLICKS", 100);

            Toast.makeText(MainActivity.this,
                    "you bought "+clicks+" clicks : ", Toast.LENGTH_SHORT)
                    .show();

            //now you have 100 clicks here from MainActivityTwo

            int total_clicks=clicks+count;


            Toast.makeText(MainActivity.this,
                    "Total Clicks Are : ", Toast.LENGTH_SHORT)
                    .show();

            textView1.setText("total clicks are => "+total_clicks);

        
    

  

而 MainActivityTwo 是

public class MainActivityTwo extends Activity 


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

Button btn = (Button) findViewById(R.id.btn);
btn.setOnClickListener(new OnClickListener() 

    @Override
    public void onClick(View v) 
        // TODO Auto-generated method stub
         Intent mIntent = new Intent();
         mIntent.putExtra("100_CLICKS", 100);
         setResult(RESULT_OK, mIntent);
         finish();

      
    );


  

在你的清单中

 <activity android:name=".MainActivityTwo"></activity>

【讨论】：

用我更新的 MainActivity 更改您的 MainActivity 并运行它并告诉我该代码是否有效

总点击次数 = 102 ... 在我再次开始点击后，答案是总点击次数 = 3

你的意思是在 total_Clicks=102 之后再次开始点击，计数从 0 开始，如果你按下点击按钮，然后是 1，然后是 2，然后是 3，依此类推

在 onActivityResult 下一行 textView1.setText("总点击次数 => "+total_clicks);写 count=total_clicks;

【参考方案2】：

使用 onSaveInstanceState 和 onRestoreInstanceState

@Override
protected void onSaveInstanceState(Bundle outState) 
    super.onSaveInstanceState(outState);

    outState.putInt("clicks", "x") // x is the int that count clicks.

还有

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) 
    super.onRestoreInstanceState(savedInstanceState);

    x = savedInstanceState.getInt("clicks");
    x + y //y is the newly bought clicks if any.

onSaveInstanceState 在 Acitivty 暂停时调用（即您将从活动 A 移动到活动 B 时。

onRestoreInstanceState 在 Activity A 恢复时被调用。也就是当你从Activity B回到Activity A时