Activity間傳值方式

  • 通過Intent意圖傳值
    方式一:
    頁面A:Intent intent = new Intent(A.this,B.class);
    intent.putExtra(kay,value);
    startActivity(intent);

             頁面B:Intent intent = getIntent();
             intent.getStringExtra(kay);
    

方式二:
頁面A:Intent intent = new Intent(A.this,B.class);
Bundle bundle = new Bundle();
bundle.putString(key,value);
input.putExtras(bundle);
startActivity(intent);

           頁面 B:Intent intent = getIntent();
           Bundle bundle = intent.getExtras();
            bundle.getString(key); 
  • 靜態成員變量傳值(不建議使用)
    方式:1.在頁面A中聲明一個公共的靜態成員變量,在合適的位置存入數據
    2.直接訪問頁面A中的靜態成員變量,讀取相應的內容

  • 全局變量傳值(Application)
    方式:1.創建Application的子類,并且在類中聲明全局變量
    public class MyApplication extends Application {

             //應用的全局變量
            public Map<String,Object> data = new HashMap<String, Object>();
    
        }
    

2.在清單文件<Application />中通過android:name="包名.類名"引入
3.在頁面A合適位置存入數據
MyApplication application = (MyApplication) getApplication();//不能new MyApplication要用getApplication得到Application對象,向下轉型得到MyApplication
application.data.put("name", "小翠");
application.data.put("age", 21);
4.在頁面B中取數據
MyApplication application = (MyApplication) getApplication();
String name = application.data.get("name").toString();
int age =Integer.parseInt(application.data.get("age").toString());

  • 回傳數據

以選取用戶頭像為例:
頁面A:startActivityForResult(intent,requestCode);
頁面B:setResult(resultCode,Intent data);
頁面A:重寫onActivityResult(requestCode,resultCode);

頁面A代碼:

     public class MainActivity extends Activity {
                private ImageView iv;   
       @Override
     protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    iv = (ImageView) findViewById(R.id.iv);
  }  
  public void show(View v)
   {
    Intent intent = new Intent(MainActivity.this, InfoActivity.class);
    
    //帶返回數據啟動Activity
    startActivityForResult(intent, 110);
   }
   /**
  * 獲取回傳的數據
  * 
  * int requestCode  請求碼
  * int resultCode   結果碼
  * Intent data     意圖(帶著返回參數)
  */
  @Override
  protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    // TODO Auto-generated method stub
    super.onActivityResult(requestCode, resultCode, data);
    if(requestCode==110 && resultCode == RESULT_OK)
    {
        //為圖片控件設置內容
        
        int imageId = data.getIntExtra("imageId", R.drawable.ic_launcher);
        
        iv.setImageResource(imageId);
    }
  }    
  }

頁面B:

public class InfoActivity extends Activity {

private RadioGroup rg;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_info);
    
    rg = (RadioGroup) findViewById(R.id.rg);
}

//點擊按鈕后,將圖片的ID 回傳給MainActivity頁面
public void submit(View v)
{
    //1, 得到當前選中的RadionButton的id
    int checkId = rg.getCheckedRadioButtonId();
    
    //圖片的ID
    int imageId = R.drawable.ic_launcher;
    
    switch (checkId) {
    
    case R.id.rb1:
        
        imageId = R.drawable.img_31;
        
        break;

    case R.id.rb2:
        
        imageId = R.drawable.img_32;
        
        break;
        
    case R.id.rb3:
        
        imageId = R.drawable.img_33;
        
        break;
        
    case R.id.rb4:
        
        imageId = R.drawable.img_42;
        
        break;
        
    case R.id.rb5:
        
        imageId = R.drawable.img_43;
        
        break;
        
    case R.id.rb6:
        
        imageId = R.drawable.img_44;
        
        break;
    }
    
    
    /**
     * 通過startActivityForResult() 開啟的界面, 需要有返回值,
     * 
     * 則必須要通過 setResult() 方法返回數據
     * 
     * resultCode  返回碼
     * 
     * data        intent意圖對象
     */
    Intent data = new Intent();
    data.putExtra("imageId", imageId);
    
    setResult(RESULT_OK, data);
    
    //關閉當前Activity頁面
    finish();
}   
}
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