数据传递与数据回传
作者：互联网
1.按照图(1)布局编写第一个Activity，点击按钮后跳转到第二个Activity并将选择的结果数据一起传递过去。
2.按照图(2)编写第二个Activity，显示第一个Activity传递的数据内容，点击按钮后跳转到第三个Activity。
3.按照图(3)编写第三个Activity，用ListView实现列表展示信息，点击列表某行信息后跳转回第二个Activity，并将列表中数据回传给第二个Activity，并且在第二个Activity中对信息进行展示。
根据上图，先写出xml布局：
第一个
1 <?xml version="1.0" encoding="utf-8"?> 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 3 android:layout_width="match_parent" 4 android:layout_height="match_parent" 5 android:orientation="horizontal"> 6 <TextView 7 android:layout_width="wrap_content" 8 android:layout_height="wrap_content" 9 android:text="水果："/> 10 11 <LinearLayout 12 android:layout_width="wrap_content" 13 android:layout_height="wrap_content" 14 android:orientation="vertical"> 15 <CheckBox 16 android:id="@+id/apple" 17 android:layout_width="wrap_content" 18 android:layout_height="wrap_content" 19 android:text="苹果"/> 20 <CheckBox 21 android:id="@+id/orange" 22 android:layout_width="wrap_content" 23 android:layout_height="wrap_content" 24 android:text="橙子"/> 25 <CheckBox 26 android:id="@+id/watermelon" 27 android:layout_width="wrap_content" 28 android:layout_height="wrap_content" 29 android:text="西瓜"/> 30 <CheckBox 31 android:id="@+id/grape" 32 android:layout_width="wrap_content" 33 android:layout_height="wrap_content" 34 android:text="葡萄"/> 35 36 <Button 37 android:id="@+id/tijiao" 38 android:layout_width="wrap_content" 39 android:layout_height="wrap_content" 40 android:text="提交" /> 41 </LinearLayout> 42 43 </LinearLayout>
第二个
1 <?xml version="1.0" encoding="utf-8"?> 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 3 android:layout_width="match_parent" 4 android:layout_height="match_parent" 5 android:orientation="vertical"> 6 7 <LinearLayout 8 android:layout_width="wrap_content" 9 android:layout_height="wrap_content" 10 android:orientation="vertical"> 11 12 <TextView 13 android:layout_width="wrap_content" 14 android:layout_height="wrap_content" 15 android:text="选择了：" /> 16 17 <TextView 18 android:id="@+id/fruit" 19 android:layout_width="wrap_content" 20 android:layout_height="wrap_content" /> 21 22 <TextView 23 android:layout_width="wrap_content" 24 android:layout_height="wrap_content" 25 android:text="商家是：" /> 26 27 <TextView 28 android:id="@+id/shop" 29 android:layout_width="wrap_content" 30 android:layout_height="wrap_content" /> 31 32 </LinearLayout>> 33 34 <Button 35 android:id="@+id/c_shop" 36 android:layout_width="wrap_content" 37 android:layout_height="wrap_content" 38 android:text="选择商家" /> 39 40 </LinearLayout>
第三个
1 <?xml version="1.0" encoding="utf-8"?> 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 3 xmlns:app="http://schemas.android.com/apk/res-auto" 4 android:orientation="horizontal" 5 android:layout_width="wrap_content" 6 android:layout_height="wrap_content"> 7 <ListView 8 android:id="@+id/shows" 9 android:layout_width="wrap_content" 10 android:layout_height="wrap_content"/> 11 12 </LinearLayout>
需要三个activity，从MainActivity开始，对应图（1）
MainActivity重点是我们要发送页面的值给SecondActivity（图2）
我们单独写一个方法buy_fruit()
1 public void buy_fruit() {
2 Intent intent_1 = new Intent(this,SecondActivity.class);
3 intent_1.putExtra("buy_fruits",buy_fruits);
4 startActivity(intent_1);
5
6 }
还有我们用多选按钮来进行选择的过程，思路就是点击按钮，将选择的水果打包起来传出去
传递数据需要用到Intent提供的putExtra()方法
1 Intent intent = new Intent(this,Activity02.class);
2 intent.putExtra("extra_data","Hello Activity02");
3 startActivity(intent);
1 Intent intent = getIntent();
2 String data = intent.getStringExtra("extra_data");
那就好说了，写代码喽
1 Button tijiao = (Button) findViewById(R.id.tijiao);
2 tijiao.setOnClickListener(new View.OnClickListener() {
3 @Override
4 public void onClick(View view) {
5 String str="";//保存所有选中的值
6 if(apple.isChecked())//选中苹果
7 str+=apple.getText().toString()+"";
8 if(orange.isChecked())//选中橘子
9 str+=orange.getText().toString()+"";
10 if(watermelon.isChecked())//选中西瓜
11 str+=watermelon.getText().toString()+"";
12 if(grape.isChecked())//选中葡萄
13 str+=grape.getText().toString();
14 buy_fruits = str;
15 if(buy_fruits.equals("")){
16 Toast.makeText(MainActivity.this,"不可以空选",Toast.LENGTH_SHORT).show();
17 }else {
18 Toast.makeText(MainActivity.this,str,Toast.LENGTH_SHORT).show();
19 buy_fruit();
20 }
21 }
22 });
好了，我们第一个activity写完了,开始写SecondActivity
这个是最难写的，它要接收两个值，第一个的和第三个的数据回传的值，所以我们可以分成两部分来写，
先写接收MainActivity的值，并显示在图（2）上
1 Intent buy_fruits = getIntent();
2 String fruits = buy_fruits.getStringExtra("buy_fruits");
3 fruit = (TextView) findViewById(R.id.fruit);
4 fruit.setText(fruits);
然后写数据回传，这个过程是点击按钮跳转到thirdActivity上，thirdActivity将数据传回来
这个过程的代码是这样的
1 Intent intent = new Intent(this,Active02.class); 2 startActivityForResult(intent,1); //这里的1就是rquestCode
//进行跳转，数据回传的开始
1 Intent intent = new Intent();
2 intent.putExtra("extra_data","Hello Activity01");
3 setResult(1,intent); //这里的1是resultCode
//另一个activity回传数据
1 protected void onActivityResult(int requestcode,int resultcode,Intent data){
2 super.onActivityResult(requestcode,resultcode,c);
3 if (requestcode == 1 && resultcode == 1){
4 String string = data.getStringExtra("extra_data");
5 }
6 }
//重写onActivityResult()方法用来接收数据
然后我们就可以根据上面的代码来写我们的代码了
1 public void c_shops() {
2 Intent intent = new Intent(this,thirdActivity.class);
3 startActivityForResult(intent,1);
4 }
5 protected void onActivityResult(int requestcode,int resultcode,Intent c){
6 super.onActivityResult(requestcode,resultcode,c);
7 if (requestcode == 1 && resultcode == 1){
8 String shops = c.getStringExtra("shop");
9 shop = (TextView) findViewById(R.id.shop);
10 shop.setText(shops);
11 }
12 }
1 public void c_shop(String oshop){
2 Intent intent = new Intent();
3 intent.putExtra("shop",oshop);
4 setResult(1,intent);
5 finish();
6 }
secondActivity主要内容也写好了
thirdActiyity主要内容也写好了
附上三个actiyity的全部代码
package com.example.app;
import androidx.appcompat.app.AppCompatActivity;
import android.support.v4.app.*;
import androidx.appcompat.app.AlertDialog;
import android.text.TextUtils;
import android.os.Bundle;
import android.view.View;
import android.widget.*;
import android.content.Intent;
public class MainActivity extends AppCompatActivity {
private CheckBox apple;
private CheckBox orange;
private CheckBox watermelon;
private CheckBox grape;
private Button tijiao;
String buy_fruits;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.homework_seven_1);
apple = (CheckBox) findViewById(R.id.apple);
orange = (CheckBox) findViewById(R.id.orange);
watermelon = (CheckBox) findViewById(R.id.watermelon);
grape = (CheckBox) findViewById(R.id.grape);
Button tijiao = (Button) findViewById(R.id.tijiao);
tijiao.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String str="";//保存所有选中的值
if(apple.isChecked())//选中苹果
str+=apple.getText().toString()+"";
if(orange.isChecked())//选中橘子
str+=orange.getText().toString()+"";
if(watermelon.isChecked())//选中西瓜
str+=watermelon.getText().toString()+"";
if(grape.isChecked())//选中葡萄
str+=grape.getText().toString();
buy_fruits = str;
if(buy_fruits.equals("")){
Toast.makeText(MainActivity.this,"不可以空选",Toast.LENGTH_SHORT).show();
}else {
Toast.makeText(MainActivity.this,str,Toast.LENGTH_SHORT).show();
buy_fruit();
}
}
});
}
public void buy_fruit() {
Intent intent_1 = new Intent(this,SecondActivity.class);
intent_1.putExtra("buy_fruits",buy_fruits);
startActivity(intent_1);
}
}
package com.example.app;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.app.AlertDialog;
import android.util.Log;
import android.text.TextUtils;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.content.Intent;
import android.widget.TextView;
public class SecondActivity extends AppCompatActivity {
private TextView fruit;
private Button c_shop;
private TextView shop;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.homework_seven_2);
Intent buy_fruits = getIntent();
String fruits = buy_fruits.getStringExtra("buy_fruits");
fruit = (TextView) findViewById(R.id.fruit);
fruit.setText(fruits);
shop = (TextView) findViewById(R.id.shop);
c_shop = (Button) findViewById(R.id.c_shop);
c_shop.setOnClickListener(new View.OnClickListener(){
public void onClick(View view) {
c_shops();
}
});
}
public void c_shops() {
Intent intent = new Intent(this,thirdActivity.class);
startActivityForResult(intent,1);
}
protected void onActivityResult(int requestcode,int resultcode,Intent c){
super.onActivityResult(requestcode,resultcode,c);
if (requestcode == 1 && resultcode == 1){
String shops = c.getStringExtra("shop");
shop = (TextView) findViewById(R.id.shop);
shop.setText(shops);
}
}
}
package com.example.app;
import android.os.*;
import android.view.View;
import android.widget.*;
import android.content.Intent;
import androidx.appcompat.app.AppCompatActivity;
public class thirdActivity extends AppCompatActivity {
private static String[] shops = new String[]{
"甘福园旗舰店","福瑞达水果汇","沁园春百果园","西域美食品"
};
private ListView lv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.homework_seven_3);
lv = (ListView) findViewById(R.id.shows);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,shops);//新建并配置ArrayAapeter
lv.setAdapter(adapter);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener(){ //设置监听
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
switch (i) {
case 0:
c_shop("甘福园旗舰店");
break;
case 1:
c_shop("福瑞达水果汇");
break;
case 2:
c_shop("沁园春百果园");
break;
case 3:
c_shop("西域美食品");
break;
}
}
});
}
public void c_shop(String oshop){
Intent intent = new Intent();
intent.putExtra("shop",oshop);
setResult(1,intent);
finish();
}
}
标签：shop,buy,fruits,传递,intent,import,回传,Intent,数据 来源： https://www.cnblogs.com/rebirther/p/12877786.html