Four common methods of transferring data between different Activitys

There are many ways to transfer data in Android. In this paper, the more common data transfer methods in 4 are introduced:

1. Transfer data through Intent

2. Passing data through static variables (static)

3. Transfer data through clipboard (Clipboard)

4. Transfer data through global objects

In TransmitDataActivity.java

package mobile.android.transmit.data;
public class TransmitDataActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button1=(Button)findViewById(R.id.button1);
Button button2=(Button)findViewById(R.id.button2);
Button button3=(Button)findViewById(R.id.button3);
Button button4=(Button)findViewById(R.id.button4);
button1.setOnClickListener(new ButtonListenner());
button2.setOnClickListener(new ButtonListenner());
button3.setOnClickListener(new ButtonListenner());
button4.setOnClickListener(new ButtonListenner());
}
class ButtonListenner implements OnClickListener{
@SuppressLint("NewApi")
@Override
public void onClick(View view) {
Intent intent=null;
switch (view.getId()) {
case R.id.button1:
intent=new Intent(TransmitDataActivity.this,MyActivity1.class);
//保存String类型的值
intent.putExtra("intent_string", "通过Intent传递的字符串");
//保存integer类型的值
intent.putExtra("intent_integer", 300);
Data data=new Data();
data.id=1000;
data.name="Android";
//保存可序列化的对象
intent.putExtra("intent_object", data);
//显示用于接收数据的Activity
startActivity(intent);
break;
case R.id.button2:
intent=new Intent();
intent.setClass(TransmitDataActivity.this, MyActivity2.class);
//下面的代码为MyActivity2中放入3个静态变量赋值
MyActivity2.id=3000;
MyActivity2.name="保时捷";
MyActivity2.data=new Data();
MyActivity2.data.id=5555;
MyActivity2.name="Android";
startActivity(intent);
break;
case R.id.button3:
intent=new Intent(TransmitDataActivity.this,MyActivity3.class);
//获取剪贴板对象（ClipboardManager）
ClipboardManager clipboard=(ClipboardManager) getSystemService(Context.CLIPBOARD_SERVICE);
//创建Data对象
Data clipboardData=new Data();
//设置Data对象中字段的值
clipboardData.id=6666;
clipboardData.name="通过Clipboard传递的数据";
//创建字节数组输出流对象，用于将Data对象转换为字节流
ByteArrayOutputStream baos=new ByteArrayOutputStream();
//用于保存Data对象生成Base64格式的字符串
String base64Str="";
try {
ObjectOutputStream oos=new ObjectOutputStream(baos);
//将Data对象写入对象输出流
oos.writeObject(clipboardData);
//将字节流进行Base64编码
base64Str=Base64.encodeToString(baos.toByteArray(), Base64.DEFAULT);
oos.close();
} catch (IOException e) {
e.printStackTrace();
}
//获取存储文本数据的剪贴板数据对象（ClipData）
ClipData clipData=ClipData.newPlainText("data", base64Str);
//设置主剪贴板
clipboard.setPrimaryClip(clipData);
//显示Myactivity3窗口
startActivity(intent);
break;
case R.id.button4:
//获取MyApp对象
MyApp myApp=(MyApp) getApplicationContext();
myApp.country="美国";
myApp.data.id=1234;
myApp.data.name="飞碟";
intent=new Intent(TransmitDataActivity.this,MyActivity4.class);
startActivity(intent);
break;
default:
break;
}
}
}
}

Data class: This class is serializable, that is, a class that implements the java.io.Serializable interface.

package mobile.android.transmit.data;
import java.io.Serializable;
public class Data implements Serializable{
public int id;
public String name;
}

In Myactivity1.java: package mobile.android.transmit.data;

public class MyActivity1 extends Activity{
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.myactivity);
TextView textView=(TextView)findViewById(R.id.textview);
// Get String Value of type 
String intentString=getIntent().getStringExtra("intent_string");
// Get Integer Value of type 
int intentInteger=getIntent().getExtras().getInt("intent_integer");
// Get Data Value of type 
Data data=(Data) getIntent().getExtras().get("intent_object");
StringBuffer sb=new StringBuffer();
sb.append("Intent_string:");
sb.append(intentString);
sb.append("\n");
sb.append("intent_integer:");
sb.append(intentInteger);
sb.append("\n");
sb.append("data.id:");
sb.append(data.id);
sb.append("\n");
sb.append("data.name:");
sb.append(data.name);
sb.append("\n");
// Output the passed value on the screen 
textView.setText(sb.toString());
}
}

In Myactivity2.java:

package mobile.android.transmit.data;
public class MyActivity2 extends Activity{
public static String name;
public static int id;
public static Data data;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.myactivity);
TextView textView=(TextView)findViewById(R.id.textview);
StringBuffer sb=new StringBuffer();
sb.append("name:");
sb.append(name);
sb.append("\n");
sb.append("id:");
sb.append(id);
sb.append("\n");
sb.append("data.id:");
sb.append(data.id);
sb.append("\n");
sb.append("data.name:");
sb.append(data.name);
sb.append("\n");
textView.setText(sb.toString());
}
}

In Myactivity3:

package mobile.android.transmit.data;
public class MyActivity3 extends Activity{
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.myactivity);
TextView textView=(TextView)findViewById(R.id.textview);
// Get Clipboard Object 
ClipboardManager clipboardManager=(ClipboardManager) getSystemService(Context.CLIPBOARD_SERVICE);
// Get from Clipboard Base64 Encoding String 
String base64Str=clipboardManager.getPrimaryClip().getItemAt(0).getText().toString();
// take Base64 Encoding strings encoded as byte arrays 
byte[] buffer=Base64.decode(base64Str, Base64.DEFAULT);
ByteArrayInputStream bais=new ByteArrayInputStream(buffer);
try {
ObjectInputStream ois=new ObjectInputStream(bais);
// Restore Byte Stream to Data object 
Data data=(Data) ois.readObject();
// take Base64 Coded text and Data Object field values are displayed in TextView In control 
textView.setText(base64Str+"\n\ndata.id:"+data.id+"\ndata.name:"+data.name);
} catch (Exception e) {
e.printStackTrace();
} 
}
}

In Myactivity4.java:

package mobile.android.transmit.data;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class MyActivity4 extends Activity{
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.myactivity);
TextView textView=(TextView) findViewById(R.id.textview);
MyApp myApp=(MyApp) getApplicationContext();
textView.setText("MyApp.country:"+myApp.country+"\nMyApp.data.id:"+myApp.data.id+"\nMyApp.data.name:"+myApp.data.name);
}
}

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