Android第五六周作业
1.返回键实现对话框弹出是否退出应用程序
package com.example.work5_1;
import android.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.content.DialogInterface;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public void onBackPressed() {
AlertDialog.Builder builder=new AlertDialog.Builder(this)
.setTitle("普通对话框")
.setMessage("是否退出至主菜单")
// .setIcon(R.drawable.ic_launcher_background)
.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
MainActivity.this.finish();
}
})
.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
AlertDialog dialog=builder.create();
dialog.show();
}
}

2.实现以下场景:从一个activity中点击一个按钮后,弹出一个单选按钮对话框,上面有“男”“女”两个选项,选定后,TOAST弹出 你选择了男,或你选择了女(参考书上改字体)
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<!-- <TextView-->
<!-- android:layout_width="wrap_content"-->
<!-- android:layout_height="wrap_content"-->
<!-- android:text="Hello World!"-->
<!-- app:layout_constraintBottom_toBottomOf="parent"-->
<!-- app:layout_constraintLeft_toLeftOf="parent"-->
<!-- app:layout_constraintRight_toRightOf="parent"-->
<!-- app:layout_constraintTop_toTopOf="parent" />-->
<Button
android:id="@+id/bt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="请选择你的性别"
android:layout_marginTop="20dp"
android:layout_gravity="center"/>
</LinearLayout>
package com.example.work5_2;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
int x = 0;
private String Arr[] = {"你选择了男","你选择了女"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(R.id.bt).setOnClickListener(this);
}
@Override
public void onClick(View v){
AlertDialog dialog;
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("性别");
builder.setSingleChoiceItems(new String[]{"男", "女"}, 0, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int i) {
x = i;
// Toast.makeText(MainActivity.this,Arr[i], Toast.LENGTH_SHORT).show();
}
});
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int i) {
// final String items[]={"男","女"};
Toast.makeText(MainActivity.this,Arr[x], Toast.LENGTH_SHORT).show();
dialog.dismiss();
}
});
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int i) {
dialog.dismiss();
}
});
dialog = builder.create();
dialog.show();
}
}

3.布局(详见:Android第五周上机word文档)
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="#4CAF50">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="1.TextView显示文本信息"
android:layout_gravity="center"
android:layout_marginTop="20dp"
android:textColor="#F50C0C"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:text="2.按钮"
android:textColor="#F30808"
android:background="#ffffff"/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="3.编辑框:请输入信息"
android:textColorHint="#F10A0A"
android:layout_margin="10dp"/>
<RadioGroup
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
<RadioButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25dp"
android:textColor="#F30707"
android:text="4.男"
android:layout_marginLeft="10dp"/>
<RadioButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25dp"
android:textColor="#F30707"
android:text="女"
android:layout_marginLeft="10dp"/>
</RadioGroup>
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="电脑"
android:textSize="20sp"
android:textColor="#F30707"
android:layout_margin="10dp"/>
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="手机"
android:textSize="20sp"
android:textColor="#F30707"
android:layout_marginLeft="10dp"/>
</LinearLayout>

4.教材p76页 图3—17购物商城界面
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<!-- tools:context=".MainActivity"-->
<!-- <TextView-->
<!-- android:layout_width="match_parent"-->
<!-- android:layout_height="45dp"-->
<!-- android:text=""-->
<!-- android:textSize="18sp"-->
<!-- android:textColor="#ffffff"-->
<!-- android:background="#ff8f03"-->
<!-- android:gravity="center"/>-->
<ListView
android:id="@+id/lv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:listSelector="#fefefefe"
></ListView>
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:padding="16dp" android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:id="@+id/iv"
android:layout_width="120dp"
android:layout_height="90dp"
android:layout_centerVertical="true"
></ImageView>
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_toRightOf="@+id/iv"
android:layout_centerVertical="true">
<TextView
android:id="@+id/title"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:textSize="20sp"
android:textColor="#000000"
android:text="桌子"></TextView>
<TextView
android:id="@+id/prices"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:layout_marginTop="10dp"
android:layout_below="@+id/title"
android:text="价格:"></TextView>
<TextView
android:id="@+id/price"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="1800"
android:textSize="20sp"
android:layout_below="@+id/title"
android:layout_toRightOf="@+id/prices"
android:textColor="#BA000000"
android:layout_marginTop="10dp"></TextView>
</RelativeLayout>
</RelativeLayout>
package com.example.shoppingapp;
import androidx.appcompat.app.AppCompatActivity;
import android.widget.TextView;
import android.widget.ImageView;
import android.widget.BaseAdapter;
import android.view.View;
import android.view.ViewGroup;
//import android.os.Build;
import android.os.Bundle;
//import android.widget.ListAdapter;
import android.widget.ListView;
public class MainActivity extends AppCompatActivity {
private ListView mListView;
private String[] titles = {"桌子","苹果","蛋糕","线衣","猕猴桃","围巾"};
private String[] prices = {"1800元","10元/kg","300元","350"+"元","10元/kg","280元"};
private int[] icons = {R.drawable.table,R.drawable.apple,R.drawable.cake,R.drawable.wireclothes,R.drawable.kiwifruit,R.drawable.scarf};
// protected void onCreate(Build savedInstanceState){
// super.onCreate(savedInstanceState);
// setContentView(R.layout.activity_main);
//
// }
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mListView = (ListView) findViewById(R.id.lv);
MyBaseAdapter mAdapter = new MyBaseAdapter();
mListView.setAdapter(mAdapter);
}
class MyBaseAdapter extends BaseAdapter {
@Override
public int getCount() {
return titles.length;
}
@Override
public Object getItem(int position) {
return titles[position];
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view= View.inflate(MainActivity.this, R.layout.list_item, null);
TextView title = (TextView) view.findViewById(R.id.title);
TextView price = (TextView) view.findViewById(R.id.price);
ImageView iv = (ImageView) view.findViewById(R.id.iv);
title.setText(titles[position]);
price.setText(prices[position]);
iv.setBackgroundResource(icons[position]);
return view;
}
}
}


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