在Activity间传递数据的四种方法及返回结果

1.通用方法

使用intent的PutExtra方法传入，用getExtra等方法获得数据

主类

Intent intent=new Intent(MainActivity.this,OtherActivity.class);
                intent.putExtra("name", "张三");
                intent.putExtra("age", 23);
                intent.putExtra("address", "北京");
                startActivity(intent);

other类

        textView=(TextView) findViewById(R.id.msg);
        Intent intent=getIntent();
        int age=intent.getIntExtra("age", 0);
        String name=intent.getStringExtra("name");
        String address=intent.getStringExtra("address");        textView.setText("age--->>"+age+"name-->>"+name+"address-->>"+address);

2.利用静态变量传递

直接在主类中设置other类中的数据，进而实现主类到other类间的数据传递

主类

Intent intent=new Intent();
                intent.setClass(MainActivity.this,OtherActivity.class);
                OtherActivity.age=23;
                OtherActivity.name="jack";
                startActivity(intent);

other类

public class OtherActivity extends Activity{
    private TextView textView;
    public static String name;
    public static int age;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.other);
        textView=(TextView) findViewById(R.id.msg);
        textView.setText("-name-->>"+name+"-age-->>"+age);
    }
}

3.使用全局变量传递

创建myApp继承Application，通过设置Application中的数据，在Activity中传递

MyApp类

package com.example.intent4;

import android.app.Application;

public class MyApp extends Application{

    public String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
    @Override
    public void onCreate() {
        super.onCreate();
        setName("张三");
    }
}

主类

myApp=(MyApp) getApplication();
                myApp.setName("jack");//修改之后的名称
                Intent intent=new Intent(MainActivity.this,OtherActivity.class);
                startActivity(intent);

other类

textView=(TextView) findViewById(R.id.msg);
        myApp=(MyApp) getApplication();
        textView.setText("-appname-->>"+myApp.getName());

4.使用剪切板(不太会用)

 5.返回结果

package com.example.intent5;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
//返回结果
public class MainActivity extends Activity {

    private EditText one,two,result;
    private Button button;
    private final static int REQUESTCODE=1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button=(Button) this.findViewById(R.id.calculate);
        one=(EditText) findViewById(R.id.one);
        two=(EditText) findViewById(R.id.two);
        result=(EditText) findViewById(R.id.result);
        button.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View v) {
                int a=Integer.parseInt(one.getText().toString());
                int b=Integer.parseInt(two.getText().toString());
                Intent intent=new Intent(MainActivity.this,OtherActivity.class);
                intent.putExtra("a", a);
                intent.putExtra("b", b);
                startActivityForResult(intent,REQUESTCODE);//可以返回结果
            }
        });
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        //用于接受回传过来的值
        if(resultCode==2){
            if(requestCode==REQUESTCODE){
                int three=data.getIntExtra("three", 0);
                result.setText(String.valueOf(three));
                
            }
        }
    }
    
    

}

package com.example.intent5;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class OtherActivity extends Activity {

    private Button button;
    private TextView textView;
    private EditText editText;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.other);
        button=(Button) this.findViewById(R.id.button1);
        textView=(TextView) this.findViewById(R.id.msg);
        editText=(EditText) findViewById(R.id.editText);
        Intent intent=getIntent();
        int a=intent.getIntExtra("a", 0);
        int b=intent.getIntExtra("b", 0);
        textView.setText(a+"+"+b+"="+"?");
        button.setOnClickListener(new View.OnClickListener() {
            
            @Override
            public void onClick(View v) {
                Intent intent=new Intent();
                int three=Integer.parseInt(editText.getText().toString());
                intent.putExtra("three", three);
                //通过Intent对象返回结果，setResult方法
                setResult(2, intent);
                finish();//结束当前Activity的生命周期
            }
        });
    }

}

注意：返回结果主类需要调用startForRexult方法及onActivityResult(),判断请求码及结果码是否正确，other类要写setResult(2, intent); finish();