Android -- Activity值传递

我们需要创建2个Activity，一个是A，一个是B。

简单的值传递

A的activity组织要传输给B的数据。
Intent i = new Intent(AMainActivity.this,BMainActivity.class);此行代码创建Intent对象，然后用于传输数据。

package com.example.testapp;import android.os.Bundle;import android.app.Activity;import android.content.Intent;import android.view.Menu;import android.view.View;public class AMainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_amain);        findViewById(R.id.button1).setOnClickListener(                new View.OnClickListener() {                    @Override                    public void onClick(View v) {                        Intent i = new Intent(AMainActivity.this,                                BMainActivity.class);                        // 传参数                        i.putExtra("name", "gaopeng");                        startActivity(i);                    }                });    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.amain, menu);        return true;    }}

B的Activity接收A传过来的数据，通过i.getStringExtra(“name”)获取数值。

package com.example.testapp;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.Menu;import android.widget.TextView;public class BMainActivity extends Activity {    private TextView t;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_bmain);        t = (TextView) findViewById(R.id.tv);        Intent i = getIntent();        t.setText(i.getStringExtra("name"));    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.bmain, menu);        return true;    }}

数据传输包Bundle

A的Activity，代码中我们用到了Bundle类，有点类似我们java中的map集合的用法。
使用putExtras或者putExtra方法将数据包放入到传输对象中。两个方法区别，一个是直接放入，另外一个是将数据包起一个别名，类似于KV的存储格式。

package com.example.testapp;import android.os.Bundle;import android.app.Activity;import android.content.Intent;import android.view.Menu;import android.view.View;public class AMainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_amain);        findViewById(R.id.button1).setOnClickListener(                new View.OnClickListener() {                    @Override                    public void onClick(View v) {                        Intent i = new Intent(AMainActivity.this,                                BMainActivity.class);                        Bundle b = new Bundle();                        b.putString("name", "gaopeng");                        b.putInt("age", 28);//                      i.putExtras(b);                        i.putExtra("user", b);                        startActivity(i);                    }                });    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.amain, menu);        return true;    }}

B的Activity，通过getBundleExtra或getExtras方法渠道Bundle对象，然后按照存放时候的名字，取出数值。

package com.example.testapp;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.Menu;import android.widget.TextView;public class BMainActivity extends Activity {    private TextView t;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_bmain);        t = (TextView) findViewById(R.id.tv);        Intent i = getIntent();        Bundle b = i.getBundleExtra("user");//      Bundle b = i.getExtras();        t.setText("name=" + b.getString("name") + ",age=" + b.getInt("age"));    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.bmain, menu);        return true;    }}

传输对象

既然是传输对象，那么我们就需要创建一个对象类。
对象类需要实现序列化接口，这里我实现的是Serializable接口，Android有自带的序列化接口Parcelable，下一篇博文，我详细说明差异及用法。

package com.example.testapp;import java.io.Serializable;import android.os.Parcel;import android.os.Parcelable;public class User implements Serializable {    // public class User implements Parcelable{    private String name;    private int age;    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    User(String name, int age) {        this.name = name;        this.age = age;    }}

A的Activity，

package com.example.testapp;import android.os.Bundle;import android.app.Activity;import android.content.Intent;import android.view.Menu;import android.view.View;public class AMainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_amain);        findViewById(R.id.button1).setOnClickListener(                new View.OnClickListener() {                    @Override                    public void onClick(View v) {                        Intent i = new Intent(AMainActivity.this,                                BMainActivity.class);                        i.putExtra("user", new User("lijingwei", 25));                        startActivity(i);                    }                });    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.amain, menu);        return true;    }}

B的Activity，通过getSerializableExtra获取对象。这种方式在我们以后的开发中应该会经常被用到。符合我们java面向对象的开发。

package com.example.testapp;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.Menu;import android.widget.TextView;public class BMainActivity extends Activity {    private TextView t;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_bmain);        t = (TextView) findViewById(R.id.tv);        Intent i = getIntent();        User user = (User) i.getSerializableExtra("user");        t.setText("name=" + user.getName() + ",age=" + user.getAge());    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.bmain, menu);        return true;    }}

附上运行时的截图

A的Activity界面

B的Activity界面