Android入門：Intent入門(2)

文章目錄

• 0.建立新的Activity步驟
• 1.最簡單的跳轉到新的Activity
• 2.帶傳回值的跳轉

 

一、Intent與Activity應用

 

0.建立新的Activity步驟

 

在應用中建立新的Acitivity很常見；

步驟1：建立一個class繼承Activity

 

步驟2：在Android-manifest.xml中添加<activity>元素

 

比如建立了一個名為SubActivity的Activity，則需要聲明如下：

        <activity android:name=".SubActivity"></activity>

 

1.最簡單的跳轉到新的Activity

程式描述：MainActivity點擊按鈕後跳轉到SubActivity，MainActivity傳遞一個（name,xiazdong）給SubActivity，並獲得顯示；

 

效果如下：

 

點擊按鈕後：

 

IntentActivity.java

package org.xiazdong;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class IntentActivity extends Activity {private Button btn1;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        btn1 = (Button)this.findViewById(R.id.brn1);        btn1.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {Intent intent = new Intent();intent.setClass(IntentActivity.this, SubActivity.class);  //從IntentActivity跳轉到SubActivityintent.putExtra("name", "xiazdong");  //放入資料startActivity(intent);  //開始跳轉}});    }}

SubActivity.java

package org.xiazdong;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.widget.TextView;public class SubActivity extends Activity{private TextView tv1;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);this.setContentView(R.layout.sub);tv1 = (TextView)this.findViewById(R.id.tv1);Intent intent = this.getIntent();    //獲得當前的Intent Bundle bundle = intent.getExtras();  //獲得全部資料String value = bundle.getString("name");  //獲得名為name的值tv1.setText(value);}}

 

2.帶傳回值的跳轉

 

跳轉到新的Activity並在結束後將傳回值傳給原Activity

程式描述：MainActivity跳轉到SubActivity後，SubActivity執行完後返回一個結果碼給IntentActivity，執行對應的過程；

程式效果：

點擊跳轉後執行完第二個Activity後再跳回第一個Activity

 

IntentActivity.java

package org.xiazdong;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;public class IntentActivity extends Activity {private Button btn1;private TextView tv1;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        btn1 = (Button)this.findViewById(R.id.brn1);        tv1 = (TextView)this.findViewById(R.id.tv2);        btn1.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {Intent intent = new Intent();intent.setClass(IntentActivity.this, SubActivity.class);startActivityForResult(intent, 100); //requestcode=100}});    }@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {super.onActivityResult(requestCode, resultCode, data);if(requestCode==100&&resultCode==200){Bundle bundle = data.getExtras();String response = bundle.getString("response");tv1.setText(response);}}    }

 

SubActivity.java

 

package org.xiazdong;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.widget.TextView;public class SubActivity extends Activity{private TextView tv1;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);this.setContentView(R.layout.sub);tv1 = (TextView)this.findViewById(R.id.tv1);Intent intent = new Intent();  //建立一個Intentintent.putExtra("response", "來自2");setResult(200,intent);  //返回碼為200finish();}}