序列化的兩種方式,使用Serializable接口和parcelable
傳遞一些基本類型數據的方法如下:
- putExtra(String name, int value)
- putExtra(String name, String value)
- putExtra(String name, float value)
- putExtra(String name, double value)
- putExtra(String name, long value)
- putExtra(String name, boolean value)
- putExtra(String name, byte value)
- putExtra(String name, char value)
傳遞基本類型ArrayList對象的方法如下:
- putIntegerArrayListExtra(String name, ArrayList《Integer》 value)
- putStringArrayListExtra(String name, ArrayList《Integer》 value)
但是我們並沒有發現直接傳遞Object類型的方法,但是在開發中經常會需要傳遞一個Object類型或者ArrayList《Object》類型的數據,那麼我們應該怎樣實現呢?
方法如下:
傳遞Object類型:
- putExtra(String name, Serializable value)
- putExtra(String name, Parcelable value)
傳遞ArrayList《Object》類型:
- putExtra(String name, Serializable value)
- putExtra(String name, Parcelable value)
- putParcelableArrayListExtra(String name, ArrayList《? extends Parcelable》 value)
下面我們將student對象從Activity傳遞給Service。
Student類
package com.example.intenttest;
public class Student implements Serializable{
private String name;
private String sex;
private int id;
public Student(String name, String sex, int id) {
super();
this.name = name;
this.sex = sex;
this.id = id;
}
@Override
public String toString() {
return "Student [name=" + name + ", sex=" + sex + ", id=" + id + "]";
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
}
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Activity類:
package com.example.intenttest;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 創建Student對象
Student student = new Student("小灰灰", "男", 1);
// 通過Intent傳遞對象給Service
Intent intent = new Intent(MainActivity.this, MyService.class);
intent.setAction("action");
intent.putExtra("student", student);
startService(intent);
}
}
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Service類:
package com.example.intenttest;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
public class MyService extends Service{
@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
if("action".equals(intent.getAction())){
Student student = (Student) intent.getSerializableExtra("student");
Log.i("tag", "學生對象的toString():"+student);
}
return super.onStartCommand(intent, flags, startId);
}
}
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結果:
將ArrayList《Object》對象從MainActivity傳遞給SecondActivity:
MainActivity類:
package com.example.intenttest;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 這裏必須爲ArrayList,不能爲List
ArrayList<Student> list = new ArrayList<Student>();
// 創建Student對象
Student student1 = new Student("小灰灰", "男", 1);
Student student2 = new Student("大灰狼", "男", 2);
Student student3 = new Student("紅太狼", "女", 3);
list.add(student1);
list.add(student2);
list.add(student3);
// 通過Intent傳遞對象給Service
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
intent.setAction("action");
intent.putExtra("studentlist", list);
startActivity(intent);
}
}
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(注意:MainActivity類中在聲明list的時候必須用ArrayList而不能用List,否則就會出現如圖所示的提示錯誤信息,
)
SecondActivity類:
package com.example.intenttest;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
public class SecondActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent = getIntent();
if ("action".equals(intent.getAction())) {
ArrayList<Student> list = (ArrayList<Student>) intent.getSerializableExtra("studentlist");
for(int i = 0;i<list.size();i++){
Log.i("tag", "student:" + list.get(i));
}
}
}
}
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運行結果:
以上是使用putExtra(String name, Serializable value)方法來進行Object和ArrayList《Object》的傳遞的代碼。
通過 putExtra(String name, Parcelable value)和putParcelableArrayListExtra(String name, ArrayList《? extends Parcelable》 value)兩個方法與putExtra(String name, Serializable value)的使用方法相同,只不過是序列化的方式不同。