使用Application通過意圖進行數據傳遞
寫個例子看一下:
Android APIS中這樣描述Application:
意思是他是用於維護全局變量的,可以在Manifest中通過修改<application>然後是他在創建應用程序時被實例化。
首先新建一個類繼承Application:
package com.example.android_app;
import android.app.Application;
public class Myapp extends Application {
public String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public void onCreate() {
// TODO Auto-generated method stub
super.onCreate();
setName("zhou");
}
}
然後注意這裏要修改Manifest文件:
<application
android:name=".Myapp"
新建兩個Activity在Main通過getApplication()引用,調用其中方法修改其中的值,再通過意圖開始另一個Activity:
package com.example.android_app;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends Activity {
private Myapp myapp;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button bt = (Button)findViewById(R.id.button1);
bt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
myapp = (Myapp)getApplication();
myapp.setName("wangan");
Intent intent = new Intent(MainActivity.this,OtherActivity.class);
startActivity(intent);
}
});
}
}
在另一個Activity中是通過getApplication()引用,調用其中的方法獲得其中的值:
package com.example.android_app;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
public class OtherActivity extends Activity {
private Myapp myapp;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_other);
myapp = (Myapp)getApplication();
TextView tv = (TextView)findViewById(R.id.textView1);
tv.setText(myapp.getName());
}
}
運行情況如下: