不同的activity传递自定义对象

有很多时候都需要在不同的Activity之间传递数据。
实现方法有很多，可以用Bundle来传递，也可以用给Intent用putExtra传递附加参数。
当然也可以传递自定义类的对象。为了让自定义类可以在Activity之间传递，必须符合一些条件。常用的方法是自定义类实现Parcelable接口或Serializable接口。Android中建议实现Parcelable。
下面例子中两种方法都有例子。
传递Parcelable过去，再传递Serializable回来。





WeightParcelable.java

Ruby代码

1. import android.os.Parcel;   
2. import android.os.Parcelable;   
3.   
4. public class WeightParcelable implements Parcelable {   
5.     private String sex;   
6.     private double height;   
7. //必须的空构造器，因为下面有一个私有的构造器，否则不能new对象   
8.     public WeightParcelable() {   
9.   
10.     }   
11.   
12.     public String getSex() {   
13.         return sex;   
14.     }   
15.   
16.     public void setSex(String sex) {   
17.         this.sex = sex;   
18.     }   
19.   
20.     public double getHeight() {   
21.         return height;   
22.     }   
23.   
24.     public void setHeight(double height) {   
25.         this.height = height;   
26.     }   
27.   
28.     @Override  
29.     public int describeContents() {   
30.         return 0;   
31.     }   
32. //需要覆盖的方法   
33.     @Override  
34.     public void writeToParcel(Parcel out, int flags) {   
35.         out.writeString(sex);   
36.         out.writeDouble(height);   
37.     }   
38. //关键的事情   
39.     public static final Parcelable.Creator<WeightParcelable> CREATOR = new Parcelable.Creator<WeightParcelable>() {   
40.         public WeightParcelable createFromParcel(Parcel in) {   
41.             return new WeightParcelable(in);   
42.         }   
43.   
44.         public WeightParcelable[] newArray(int size) {   
45.             return new WeightParcelable[size];   
46.         }   
47.     };   
48. //   
49.     private WeightParcelable(Parcel in) {   
50.         sex = in.readString();   
51.         height = in.readDouble();   
52.     }   
53. }  

import android.os.Parcel;import android.os.Parcelable;public class WeightParcelable implements Parcelable {private String sex;private double height;//必须的空构造器，因为下面有一个私有的构造器，否则不能new对象public WeightParcelable() {}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}public double getHeight() {return height;}public void setHeight(double height) {this.height = height;}@Overridepublic int describeContents() {return 0;}//需要覆盖的方法@Overridepublic void writeToParcel(Parcel out, int flags) {out.writeString(sex);out.writeDouble(height);}//关键的事情public static final Parcelable.Creator<WeightParcelable> CREATOR = new Parcelable.Creator<WeightParcelable>() {public WeightParcelable createFromParcel(Parcel in) {return new WeightParcelable(in);}public WeightParcelable[] newArray(int size) {return new WeightParcelable[size];}};//private WeightParcelable(Parcel in) {sex = in.readString();height = in.readDouble();}}

HeightSerializable.java

Java代码

1. import java.io.Serializable;   
2.   
3. public class HeightSerializable implements Serializable {   
4.     private static final long serialVersionUID = 8502706820090766507L;   
5.     private String sex;   
6.     private double weight;   
7.   
8.     public String getSex() {   
9.         return sex;   
10.     }   
11.   
12.     public void setSex(String sex) {   
13.         this.sex = sex;   
14.     }   
15.   
16.     public double getWeight() {   
17.         return weight;   
18.     }   
19.   
20.     public void setWeight(double weight) {   
21.         this.weight = weight;   
22.     }   
23.   
24. }  

import java.io.Serializable;public class HeightSerializable implements Serializable {private static final long serialVersionUID = 8502706820090766507L;private String sex;private double weight;public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}public double getWeight() {return weight;}public void setWeight(double weight) {this.weight = weight;}}

EX03_10.java

Java代码

1. import android.app.Activity;   
2. import android.content.Intent;   
3. import android.os.Bundle;   
4. import android.util.Log;   
5. import android.view.View;   
6. import android.widget.Button;   
7. import android.widget.EditText;   
8. import android.widget.RadioButton;   
9. import android.widget.TextView;   
10.   
11. public class EX03_10 extends Activity {   
12.     /** Called when the activity is first created. */  
13.     public static final String parcelableKey = "irdc.ex03_10.parcelableKey";   
14.     public static final String seralizableKey = "irdc.ex03_10.seralizableKey";   
15.     private static final String TAG = "EX03_10";   
16.   
17.     @Override  
18.     public void onCreate(Bundle savedInstanceState) {   
19.         super.onCreate(savedInstanceState);   
20.         setContentView(R.layout.main);   
21.   
22.         Button b1 = (Button) findViewById(R.id.button1);   
23.         b1.setOnClickListener(new Button.OnClickListener() {   
24.             public void onClick(View v) {   
25.                 EditText et = (EditText) findViewById(R.id.height);   
26.                 double height = Double.parseDouble(et.getText().toString());   
27.                 String sex = "";   
28.                 RadioButton rb1 = (RadioButton) findViewById(R.id.sex1);   
29.                 if (rb1.isChecked()) {   
30.                     sex = "M";   
31.                 } else {   
32.                     sex = "F";   
33.                 }   
34.                 Intent intent = new Intent();   
35.                 intent.setClass(EX03_10.this, EX03_10_1.class);   
36.   
37.                 Bundle bundle = new Bundle();   
38.   
39.                 WeightParcelable wp = new WeightParcelable();   
40.                 wp.setSex(sex);   
41.                 wp.setHeight((int) height);   
42.   
43.                 bundle.putParcelable(parcelableKey, wp);   
44.                 intent.putExtras(bundle);   
45. //注意这里   
46.                 startActivityForResult(intent, 1);   
47.             }   
48.         });   
49.     }   
50. //这个是关键   
51.     @Override  
52.     protected void onActivityResult(int requestCode, int resultCode, Intent data) {   
53.         Log.d(TAG, "onActivityResult requestCode=" + requestCode   
54.                 + " resultCode= " + resultCode + " data == null["  
55.                 + (data == null) + "]");   
56.   
57.         super.onActivityResult(requestCode, resultCode, data);   
58.         if (requestCode == 1) {   
59.             if (resultCode == RESULT_OK) {   
60.                 try {   
61.                     HeightSerializable hs = (HeightSerializable) data   
62.                             .getSerializableExtra(seralizableKey);   
63.   
64.                     TextView textView4 = (TextView) findViewById(R.id.text4);   
65.                     textView4.setText("性别：" + hs.getSex() + "/n标准体重:"  
66.                             + hs.getWeight());   
67.   
68.                 } catch (Exception e) {   
69.                     e.printStackTrace();   
70.                 }   
71.             }   
72.         }   
73.     }   
74.   
75. }  

import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.RadioButton;import android.widget.TextView;public class EX03_10 extends Activity {/** Called when the activity is first created. */public static final String parcelableKey = "irdc.ex03_10.parcelableKey";public static final String seralizableKey = "irdc.ex03_10.seralizableKey";private static final String TAG = "EX03_10";@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);Button b1 = (Button) findViewById(R.id.button1);b1.setOnClickListener(new Button.OnClickListener() {public void onClick(View v) {EditText et = (EditText) findViewById(R.id.height);double height = Double.parseDouble(et.getText().toString());String sex = "";RadioButton rb1 = (RadioButton) findViewById(R.id.sex1);if (rb1.isChecked()) {sex = "M";} else {sex = "F";}Intent intent = new Intent();intent.setClass(EX03_10.this, EX03_10_1.class);Bundle bundle = new Bundle();WeightParcelable wp = new WeightParcelable();wp.setSex(sex);wp.setHeight((int) height);bundle.putParcelable(parcelableKey, wp);intent.putExtras(bundle);//注意这里startActivityForResult(intent, 1);}});}//这个是关键@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent data) {Log.d(TAG, "onActivityResult requestCode=" + requestCode+ " resultCode= " + resultCode + " data == null["+ (data == null) + "]");super.onActivityResult(requestCode, resultCode, data);if (requestCode == 1) {if (resultCode == RESULT_OK) {try {HeightSerializable hs = (HeightSerializable) data.getSerializableExtra(seralizableKey);TextView textView4 = (TextView) findViewById(R.id.text4);textView4.setText("性别：" + hs.getSex() + "/n标准体重:"+ hs.getWeight());} catch (Exception e) {e.printStackTrace();}}}}}

EX03_10_1.java

Java代码

1. import java.text.DecimalFormat;   
2. import java.text.NumberFormat;   
3.   
4. import android.app.Activity;   
5. import android.content.Intent;   
6. import android.os.Bundle;   
7. import android.util.Log;   
8. import android.widget.TextView;   
9.   
10. public class EX03_10_1 extends Activity {   
11.     private static final String TAG = "EX03_10_1";   
12.   
13.     @Override  
14.     public void onCreate(Bundle savedInstanceState) {   
15.         super.onCreate(savedInstanceState);   
16.         setContentView(R.layout.myalyout);   
17.   
18.         WeightParcelable wp = (WeightParcelable) getIntent()   
19.                 .getParcelableExtra(EX03_10.parcelableKey);   
20.   
21.         String sex = wp.getSex();   
22.         double height = wp.getHeight();   
23.   
24.         String sexText = "";   
25.         if (sex.equals("M")) {   
26.             sexText = "男性";   
27.         } else {   
28.             sexText = "女性";   
29.         }   
30.   
31.         String weight = this.getWeight(sex, height);   
32.   
33.         TextView tv1 = (TextView) findViewById(R.id.text1);   
34.         tv1.setText("性别:" + sexText + "/n身高:" + height + "厘米/n标准体重: " + weight   
35.                 + "公斤");   
36.   
37.         // 返回对象   
38.         Intent data = new Intent();   
39.         HeightSerializable hs = new HeightSerializable();   
40.         hs.setSex(sexText);   
41.         hs.setWeight(Double.valueOf(weight));   
42.   
43.         data.putExtra(EX03_10.seralizableKey, hs);   
44. //从这里返回对象   
45.         setResult(RESULT_OK, data);   
46.     }   
47.   
48.     private String format(double num) {   
49.         NumberFormat formatter = new DecimalFormat("0.00");   
50.         String s = formatter.format(num);   
51.         return s;   
52.     }   
53.   
54.     private String getWeight(String sex, double height) {   
55.         String weight = "";   
56.         if (sex.equals("M")) {   
57.             weight = format((height - 80) * 0.7);   
58.         } else {   
59.             weight = format((height - 70) * 0.6);   
60.         }   
61.         return weight;   
62.     }   
63. }