包裹(Bundle)

包裹(Bundle)

包裹(Bundle)是字符串值(String value)對各種可包裹類型的映射(Mapping). 在活動(Activity)之間的數據傳遞就往往用上包裹(Bundle).

修改變先前的應用程序"活動(activity)和意圖(intent)", 以使用包裹傳遞數據.



修改主佈局(main.xml), 添加一個編輯文本(EditText).

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/hello"
  />
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="Your Name?"
  />
<EditText
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:id="@+id/inamefield"
  />
<Button
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="Launch Activity2"
  android:id="@+id/launchbutton"
  />
</LinearLayout>

修改主活動代碼, 使用Intent.putExtra()傳遞數據給Activity2.

package com.AndroidIntent;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class AndroidIntent extends Activity {
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
      Button launchButton = (Button)findViewById(R.id.launchbutton);
      final EditText iNameField = (EditText)findViewById(R.id.inamefield);
      launchButton.setOnClickListener(new Button.OnClickListener(){

  @Override
  public void onClick(View arg0) {
   // TODO Auto-generated method stub
   Intent newIntent = new Intent(AndroidIntent.this, Activity2.class);
   newIntent.putExtra("name", iNameField.getText().toString());
   startActivity(newIntent);
  }});
  }
}

修改layout2.xml, 添加一個文本視圖(TextView).

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  >
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="It's Activity2"
  />
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:id="@+id/onamefield"
  />
</LinearLayout>

修改Activity2代碼, 使用getIntent().getExtras()獲得數據, 並顯示在文本視圖(TextView)中.

package com.AndroidIntent;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;


public class Activity2 extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
 // TODO Auto-generated method stub
 super.onCreate(savedInstanceState);
 setContentView(R.layout.layout2);
 TextView oNameField = (TextView)findViewById(R.id.onamefield);

 Bundle extras = getIntent().getExtras();
 oNameField.setText("Hello " + extras.getString("name"));
}
}

記住, 需要修改清單文件(AndroidManifest.xml)加入ctivity2, 參考"活動(activity)和意圖(intent)".

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