使用Intent傳值及回傳值

簡單傳值

FirstActivity.java

        findViewById(R.id.button).setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(FirstActivity.this, SecondActivity.class);
                intent.putExtra("extra_data","data"); // 傳字符串, 更多傳值方法
                startActivity(intent);
            }
        });

SecondActivity.java

  @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
        // 獲取Intent對象
        Intent intent = getIntent();
        // 根據key獲取value
        String extra_data = intent.getStringExtra("extra_data");
        // 獲取一個沒有的可以 結果 null
        String extra_data2 = intent.getStringExtra("extra_data2");
        Log.i(TAG, "onCreate: " + extra_data + extra_data2);
   }

回傳值:

修改FirstActivity.java

/**
 * 監聽獲取activity返回的數據
 * @param requestCode 傳入的請求碼
 * @param resultCode 處理結果碼
 * @param data intent數據
 */
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
        case 1:
            if (resultCode == RESULT_OK) {
                String resultData = data.getStringExtra("data_return");
                Log.i(TAG, "onActivityResult: " + resultData);
            }
            break;
        default:
    }
}

修改SecondActivity.java

        button = (Button) findViewById(R.id.button2);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.putExtra("data_return", "hello FirstActivity");
                // 給上一個活動返回數據
                setResult(RESULT_OK, intent);// 回調(FirstActivity.java中)onActivityResult方法
                finish();
            }
        });