Android Bundle類學習

今天發現自己連Bundle類都沒有搞清楚，於是花時間研究了一下。

根據google官方的文檔（http://developer.android.com/reference/android/os/Bundle.html）

Bundle類是一個key-value對，“A mapping from String values to various Parcelable types.”

兩個activity之間的通訊可以通過bundle類來實現：

開始做了一個demo來模擬activity互相傳遞。

Activity1

public class Activity1 extends Activity {
	Button bt_1;
	EditText et_1;
	TextView tv_1;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.pass1);
		bt_1 = (Button) findViewById(R.id.bt_1);
		et_1 = (EditText) findViewById(R.id.et_1);
		tv_1 = (TextView) findViewById(R.id.tv_1);
		try {
			// 獲取返回值
			Bundle bundle = this.getIntent().getExtras();
			// 獲取數據內容
			String userReturn = bundle.getString("userReturn");
			// 顯示在TextView中
			tv_1.setText("傳回：" + userReturn);
		} catch (Exception e) {
			System.out.println("error:" + e);
		}
		bt_1.setOnClickListener(new View.OnClickListener() {

			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				// 創建Intent
				Intent intent = new Intent();
				// 升職from和to的activity
				intent.setClass(Activity1.this, Activity2.class);
				// 設置要傳送的數據
				Bundle bundle = new Bundle();
				bundle.putString("userInput", et_1.getText().toString());
				// 將數據設置到Intent中
				intent.putExtras(bundle);

				Activity1.this.startActivity(intent);
				Activity1.this.finish();
			}
		});

	}

}

Activity2

public class Activity2 extends Activity {
	Button bt_2;
	TextView tv_2;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.pass2);
		tv_2 = (TextView) findViewById(R.id.tv_2);
		bt_2 = (Button) findViewById(R.id.bt_2);
		Bundle bundle = this.getIntent().getExtras();
		// 獲取數據
		final String userInput = bundle.getString("userInput");
		// 顯示在TextView中
		tv_2.setText(userInput);

		bt_2.setOnClickListener(new View.OnClickListener() {

			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				// 創建Intent實體
				Intent intent = new Intent();

				intent.setClass(Activity2.this, Activity1.class);

				// 創建要傳回的數據
				Bundle bundle = new Bundle();
				bundle.putString("userReturn", "return value " + userInput);

				intent.putExtras(bundle);

				Activity2.this.startActivity(intent);
				Activity2.this.finish();
			}
		});

	}
}

這個demo可以完成兩個Activity之間的互相調用，但是無法說明是誰傳遞過來的數據，有可能是別的activity傳遞過來的數據。

所以上網查了下相關文檔，添加了一下內容，主要用的是startActivityForResult來實現

Activity1中修改

<pre name="code" class="java" style="color: rgb(51, 51, 51); font-size: 14px; line-height: 26px;"><pre name="code" class="java">				//Activity1.this.startActivity(intent);
				Activity1.this.startActivityForResult(intent, 123456);
				//Activity1.this.finish();

Activity2中修改

<pre name="code" class="java">				//Activity2.this.startActivity(intent);
				Activity2.this.setResult(123456, intent);
				Activity2.this.finish();

之後需要在Activity1中重寫 onActivityResult方法替代原有的try catch

	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		// TODO Auto-generated method stub
		super.onActivityResult(requestCode, resultCode, data);
		
		if(resultCode == 123456){
			Bundle bundle = data.getExtras();
			String userReturn  = bundle.getString("userReturn");
			tv_1 = (TextView) findViewById(R.id.tv_1);
			tv_1.setText("傳回："+userReturn);
			
		}
	}