Android - 通過兩個活動之間的putExtras傳遞幾個參數

Question

在MainActivity和ChangeBrush之間傳遞畫筆大小和畫筆形狀。

主營：

static final int ACTIVITY_BRUSH_SIZE_REQUEST_CODE = 2; 
static final int ACTIVITY_BRUSH_SHAPE_REQUEST_CODE = 3; 

public void onClickBrush(View view) { 
    Intent intent = new Intent(MainActivity.this, ChangeBrush.class); 

    startActivityForResult(intent, ACTIVITY_BRUSH_SIZE_REQUEST_CODE); 
    startActivityForResult(intent, ACTIVITY_BRUSH_SHAPE_REQUEST_CODE); 
} 

ChangeBrush：

public void onClickChangeBrushSize(View view) { 
    String size = view.getTag().toString().; 

    // return the brush size to main activity 
    Bundle bundle = new Bundle(); 
    bundle.putString("size", size); 

    Intent intent = new Intent(); 
    intent.putExtras(bundle); 
    setResult(Activity.RESULT_OK, intent); 

    finish(); 
} 

public void onClickChangeBrushShape(View view) { 
    String shape = view.getTag().toString(); 

    // return the brush shape to main activity 
    Bundle bundle = new Bundle(); 
    bundle.putString("shape", shape); 

    Intent intent = new Intent(); 
    intent.putExtras(bundle); 
    setResult(Activity.RESULT_OK, intent); 

    finish(); 
} 

SelectBrush活動佈局：

當用戶點擊size按鈕，在按鈕活動，他們可以通過size和shape到MainActivity。在MainActivity中，我使用onActivityResult來設置畫筆大小和形狀。

@Override 
protected void onActivityResult(int requestCode, int resultCode, Intent data) { 
    if (resultCode == RESULT_OK) { 

     Bundle bundle = data.getExtras(); 
     String color = bundle.getString("color"); 
     String size = bundle.getString("size"); 
     String shape = bundle.getString("shape"); 

     switch(requestCode) { 
      case ACTIVITY_COLOR_REQUEST_CODE: 
       fingerPainterView.setColour(Color.parseColor(color)); // set new color value 

      case ACTIVITY_BRUSH_SIZE_REQUEST_CODE: 
       Log.d("FingerPainter", "Main activity change brush size to " + size); 

      case ACTIVITY_BRUSH_SHAPE_REQUEST_CODE: 
       Log.d("FingerPainter", "Main activity change brush shape to " + shape); 
     } 

    } else if(resultCode == RESULT_CANCELED) { 
     Log.d("FingerPainter", "MainActivity canceled"); 

    } 
} 

這將記錄的返回值：

D/FingerPainter: Main activity change brush shape to null 
D/FingerPainter: Main activity change brush size to null 
D/FingerPainter: Main activity change brush shape to SQUARE 

看來返回值可以對應於正確的意圖。我不知道爲什麼它記錄了兩次形狀信息。 finish()有什麼不對嗎？我希望用戶選擇大小和形狀，然後返回到主要活動。

如果方法錯了，應該怎麼做才能通過這兩個值？

Answer 1

兩個問題我看到：

1：要調用startActivityForResult兩次。您可以使用intent.putExtra(...)來傳遞額外資訊。

2：你沒有break在switch聲明：

switch(requestCode) { 
    case ACTIVITY_COLOR_REQUEST_CODE: 
     fingerPainterView.setColour(Color.parseColor(color)); // set new color value 
    break; 
    case ACTIVITY_BRUSH_SIZE_REQUEST_CODE: 
     Log.d("FingerPainter", "Main activity change brush size to " + size); 
    break; 
    case ACTIVITY_BRUSH_SHAPE_REQUEST_CODE: 
     Log.d("FingerPainter", "Main activity change brush shape to " + shape); 
    break; 
} 

Answer 2

如果你正試圖從一個單一的意向更新多件事情，我認爲你需要保存關閉當前數據已在活動中存在。

public void onClickBrush(View view) { 
    Intent intent = new Intent(MainActivity.this, ChangeBrush.class); 
    // intent.putExtra("shape", currentShape); // for example 

    // then, only start one Activity, with a generic request code, not one Activity twice with two codes 

換句話說，您啓動一​​個能夠更改所有數據的活動（即使您一次只更新一個值）。因此，在開始下一個活動時保存當前值，並在更新新值時將其保持原樣。那麼你不應該得到空值。

例如，形狀按鈕。

public void onClickChangeBrushShape(View view) { 
    String shape = view.getTag().toString(); 

    // return the brush shape to main activity 
    Bundle bundle = new Bundle(); 

    bundle.putString("shape", shape); // Set the new shape 

    bundle.putString("color", color); // I assume you've saved this 
    bundle.putString("size", size); // and this... 

    // You could put string extras into the intent directly, but whatever 
    Intent intent = new Intent(); 
    intent.putExtras(bundle); 
    setResult(Activity.RESULT_OK, intent); 

    finish(); 
} 

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另一種選擇是使用SharedPreferences存儲所有的值，而忘記了意圖和捆綁。