Question

使用以下网址 How to send an object from one Android Activity to another using Intents?

我已经按照以下方式进行了示例应用

Scrollview1.java

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 Scrollview1 extends Activity {
    static int i;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button b = (Button)findViewById(R.id.Button01);

        b.setOnClickListener(new OnClickListener(){

            public void onClick(View v) {
                Intent i = new Intent(Scrollview1.this, Result.class);
                Name n = new Name();
                n.setI(20);
                n.setS1("Hello");
                n.setS2("World");
                i.putExtra("Name", n);
                startActivity(i);
            }           
        });
    }
}

// Name.java

import android.os.Parcel;
import android.os.Parcelable;

public class Name implements Parcelable{
    int i;
    String s1;
    String s2;
    public Name(){

    }
    private Name(Parcel in){
        in.readInt();
        in.readString();
    }
    public int getI() {
        return i;
    }
    public void setI(int i) {
        this.i = i;
    }

    public String getS1() {
        return s1;
    }
    public void setS1(String s) {
        this.s1 = s;
    }
    public String getS2() {
        return s2;
    }
    public void setS2(String s) {
        this.s2 = s;
    }

    public int describeContents() {
        return 0;
    }
    public void writeToParcel(Parcel dest, int flags) {     
        dest.writeInt(i);
        dest.writeString(s1);
        dest.writeString(s2);
    }

      public static final Name.Creator<Name> CREATOR = new Name.Creator<Name>() {
            public Name createFromParcel(Parcel in) {
                return new Name(in);
            }

            public Name[] newArray(int size) {
                return new Name[size];
            }
        };  
}

// Result.java

import android.app.Activity;
import android.os.Bundle;

public class Result extends Activity{
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

      Name a = (Name)getIntent().getParcelableExtra("Name");
      System.out.println("Int : "+a.getI());
      System.out.println("String : "+a.getS1());
      System.out.println("String : "+a.getS2());
    }
}

但是Result类I变为null。有什么问题？

Answer 1

在：

private Name(Parcel in){
    in.readInt();
    in.readString();
}

您正在从包裹中读取，但实际上并未将信息分配给变量。

Answer 2

我认为你应该改变它。

private Name(Parcel in){
   i= in.readInt();
   s1 =  in.readString();
   s2 = in.readString();
}

Answer 3

根据getParcelableExtra的文档，它声明如果未找到parcelable内容，则返回null。

在Result.java中尝试此操作

Name a = (Name)getIntent().getExtras().getParcelable("Name");

而不是您现在正在做的事情Name a = (Name)getIntent().getParcelableExtra("Name");

我希望这有帮助。告诉我它是否有用

如何使用Intent.putExtra和Parcel将对象从一个Activity发送到另一个Activity？

3 个答案: