Android入门1_传递数据的几种方式

来源：互联网发布：网络维护员的工作怎样编辑：程序博客网时间：2024/06/01 08:21

使用的是AndroidStudio2.0版本。

1. 通过Intent的Intent.Extra方法传递数据。

首先应该明白什么是Intent意图，android中的每个应用都是运行在一个单独的虚拟机中，一个应用的activity想打开本应用活着其他应用的activity就需要使用intent传递一个指令，从而打开activity。

我们想实现，在一个activity中点击一个按钮，将输入好的值显示在另个activity中。

新建一个工程，在MainActivity填写：

package com.shiyang.android_intent1;import android.content.Intent;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;public class MainActivity extends AppCompatActivity {    private Button button;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        button = (Button)findViewById(R.id.button);        button.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                Intent intent = new Intent(MainActivity.this, OtherActivity.class);                intent.putExtra("name","Jack");//存放键值对                 intent.putExtra("age",23);                intent.putExtra("address","sanya");                startActivity(intent);            }        });    }}

新建一个activity为OtherActivity，填写代码：

package com.shiyang.android_intent1;import android.content.Intent;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;import android.widget.TextView;public class OtherActivity extends AppCompatActivity {    TextView textView ;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_other);        textView = (TextView)findViewById(R.id.Msg);        Intent intent = getIntent();        String name = intent.getStringExtra("name");        int age = intent.getIntExtra("age",0);        String address = intent.getStringExtra("address");        textView.setText("name is " + name + "age is "  +age+" address is " + address);    }}

2.主要学习利用剪贴板传送数据，病学会使用android的ObjectOutputStream嵌套ByteArrayOutputStream。使用Base64完成字节数组和String 的相互转换.

MainActivity:

 private Button button;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        button = (Button) findViewById(R.id.button);        button.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {//                ClipboardManager clipboardManager = (ClipboardManager) getSystemService(Context.CLIPBOARD_SERVICE);//                String name = "jack";//                ClipData clipData = ClipData.newPlainText("new Plain Text Lable",name);//                clipboardManager.setPrimaryClip(clipData);//                Intent intent = new Intent(MainActivity.this,OtherActivity.class);//                startActivity(intent);                MyData myData = new MyData("Jack",23);                //将对象转换为字符串                ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();                String base64string = "";                try {                    ObjectOutputStream objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);                    objectOutputStream.writeObject(myData);                    base64string = Base64.encodeToString(byteArrayOutputStream.toByteArray(),Base64.DEFAULT);                    objectOutputStream.close();                }catch (Exception e){                }                ClipboardManager clipboardManager = (ClipboardManager)getSystemService(Context.CLIPBOARD_SERVICE);                ClipData clipData = ClipData.newPlainText("Label", base64string);                clipboardManager.setPrimaryClip(clipData);                Intent intent = new Intent(MainActivity.this,OtherActivity.class);                startActivity(intent);            }        });    }

OtherActivity:

    private TextView textView;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.other);        textView = (TextView)findViewById(R.id.msg);        ClipboardManager clipboardManager = (ClipboardManager)getSystemService(Context.CLIPBOARD_SERVICE);        ClipData clipData =  clipboardManager.getPrimaryClip();        String data = (String)clipboardManager.getPrimaryClip().getItemAt(0).getText();        byte[] base64 = Base64.decode(data,Base64.DEFAULT);        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(base64);        try{            ObjectInputStream objectInputStream = new ObjectInputStream(byteArrayInputStream);            MyData myData = (MyData) objectInputStream.readObject();            textView.setText(myData.toString());        }catch (Exception e){        }    }

MyData:注意要继承序列化接口

public class MyData implements Serializable {    public MyData(String name, int age) {        this.name = name;        this.age = 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;    }    private String name;    private int age;    @Override    public String toString() {        return "Mydata [name =" + name +",age = " + age +"]";    }}

3. 利用Intent的startActivityForResult方法传递数据。这里做个例子，一个activity的数据发送到另一个，另一个再返回回来。

MainActivity：

public class MainActivity extends AppCompatActivity {    private final static int REQUEST_CODE = 1;    private EditText oneEditText;    private EditText twoEditText;    private EditText resultEditText;    private Button button;    private int oneNum;    private int twoNum;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        oneEditText = (EditText)findViewById(R.id.oneAddEditText);        twoEditText = (EditText)findViewById(R.id.twoAddEditText);        resultEditText = (EditText)findViewById(R.id.resultEditText);        button = (Button)findViewById(R.id.button2);        button.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                oneNum = Integer.parseInt(oneEditText.getText().toString());                twoNum = Integer.parseInt(twoEditText.getText().toString());                Intent intent = new Intent(MainActivity.this,OtherActivity.class);                intent.putExtra("One",oneNum);                intent.putExtra("One",twoNum);                startActivityForResult(intent,REQUEST_CODE);            }        });    }    @Override    protected void onActivityResult(int requestCode, int resultCode, Intent data) {        super.onActivityResult(requestCode, resultCode, data);        if(resultCode == 2){            if(requestCode == REQUEST_CODE){                int three = data.getIntExtra("Three",0);                resultEditText.setText(String.valueOf(three));            }        }    }}

OtherActivity：

public class OtherActivity extends AppCompatActivity {    private EditText resultEditText;    private Button returnMainBtn;    private final static int resultCode = 2;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_other);        resultEditText = (EditText)this.findViewById(R.id.ResultEditText2);        returnMainBtn = (Button)this.findViewById(R.id.returnMainBtn);        Intent intent = getIntent();        int one = intent.getIntExtra("One",0);        int two = intent.getIntExtra("Two",0);        int result;        result = one+two;        //resultEditText.setText(result);        //resultEditText.setText(result);        returnMainBtn.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                int three = Integer.parseInt(resultEditText.getText().toString());                Intent inte = new Intent();                inte.putExtra("Three",three);                setResult(resultCode,inte); // 通过intent返回意图结果，通过setResult                finish();//结束当前activity                //startActivityForResult(inte,resultCode);            }        });    }}

重点在于，MainActivity中的resultCode要和OtherActivity的setOnClickListener方法中的SetResult参数一致，这样返会MainActivity中就可以对应。

4. 使用静态变量：

///使用intent传递数据是官方推荐，
//但是intent不能传递不能序列化的对象
//我们可以使用静态变量来解决这样的问题

MainActivity：

public class MainActivity extends AppCompatActivity {    private Button button;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        button = (Button)this.findViewById(R.id.button);        button.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                OtherActivity.name = "Jack";                OtherActivity.age = 23;                Intent intent = new Intent();                intent.setClass(MainActivity.this,OtherActivity.class);                startActivity(intent);            }        });    }}

OtherActivity：

public class OtherActivity extends AppCompatActivity {    public static String name;    public static int age;    public TextView textView;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_other);        textView = (TextView) this.findViewById(R.id.Text);        textView.setText("name is " + name + " Age is " + age);    }}

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