56作业

package cn.itcast.myapplication;

import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

import android.content.DialogInterface;
import android.os.Bundle;

public class Main5Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main5);
    }
    public void onBackPressed(){
        AlertDialog dialog;
        AlertDialog.Builder builder=new AlertDialog.Builder(this);
        builder.setTitle("普通对话框");
        builder.setIcon(R.mipmap.ic_launcher);
        builder.setMessage("是否退出应用");
        builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog,int which) {
                dialog.dismiss();
                Main5Activity.this.finish();
            }
        });
        
        builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog,int which) {
              dialog.dismiss();
            }
        });
        dialog=builder.create();
        dialog.show();



    }



}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_height="match_parent"
    android:layout_width="match_parent">
<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="按钮1"
    android:layout_centerInParent="true"
    android:background="#777BB9">

</Button>
</RelativeLayout>

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（参考书上改字体那个案例）

 

<?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=".Main3Activity">
    <TextView
        android:id="@+id/tv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="您的性别是："
        android:gravity="center"
        android:textSize="20sp"
        android:layout_marginTop="10dp"
        android:textColor="#FFFDB371"/>
    <Button
        android:id="@+id/bt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="选择性别"
        android:layout_gravity="center"
        android:layout_marginTop="10dp"/>
 
</LinearLayout>

package com.example.myapplication;
 
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.TextView;
 
public class Main3Activity extends AppCompatActivity implements View.OnClickListener {
    private TextView textView;
    private String[] sexArry= {"男", "女"};
    int sex = 1;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main3);
        findViewById(R.id.bt).setOnClickListener(this);
        textView = (TextView) findViewById(R.id.tv);
    }
 
    @Override
    public void onClick(View v) {
        AlertDialog dialog;
        AlertDialog.Builder builder=new AlertDialog.Builder(this)
                .setTitle("选择性别")
                .setIcon(R.mipmap.ic_launcher)
                .setSingleChoiceItems(new String[]{"男", "女"}, sex, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int i) {
                        sex=i;
                    }
                })
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int i) {
                        dialog.dismiss();//关闭对话框
                        if (sex==1){
                            textView.setText("您的性别是：女");
                        }else{
                            textView.setText("您的性别是：男");
                        }
                    }
                })
                //t添加"取消"按钮
                .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)

package com.example.myapplication;

import android.os.Bundle;
import android.app.Activity;

public class Assignment03_04 extends Activity {
    int gender = 0;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity03_04);
    }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".Assignment03_04" >
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/textView"
        android:layout_marginTop="25dp"
        android:textSize="25sp"
        android:gravity="center"
        />
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/button"
        android:layout_margin="25dp"
        />
    <EditText
        android:inputType="text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="@string/editText"
        android:gravity="center"
        />
    <RadioGroup
        android:id="@+id/radioGroup"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        >
        <RadioButton
            android:id="@+id/radioButton0"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="25sp"
            android:text="@string/male" 
            />
        <RadioButton
            android:id="@+id/radioButton1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="25sp"
            android:text="@string/female" 
            />
    </RadioGroup>
    <CheckBox
        android:id="@+id/checkBox0"
        android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="25sp"
            android:text="@string/checkBox0"
        />
    <CheckBox
        android:id="@+id/checkBox1"
        android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="25sp"
            android:text="@string/checkBox1"
        />

</LinearLayout>

 

4.

package com.example.myapplication;

import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

public class Assignment03_01 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.ic_launcher_foreground, R.drawable.ic_launcher_foreground,  R.drawable.ic_launcher_foreground, R.drawable.ic_launcher_foreground,  R.drawable.ic_launcher_foreground, R.drawable.ic_launcher_foreground };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity03_01);
        mListView = findViewById(R.id.listView);
        MyBaseAdapter mAdapter = new MyBaseAdapter();
        mListView.setAdapter(mAdapter);
    }
    class ViewHolder {
        TextView textViewTitle;
        TextView textViewContent;
        ImageView imageView;
    }
    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) {
            ViewHolder holder = null;
            if (convertView == null) {
                convertView = View.inflate(Assignment03_01.this, R.layout.list_item, null);
                holder = new ViewHolder();
                holder.textViewTitle = convertView.findViewById(R.id.textViewTitle);
                holder.textViewContent = convertView.findViewById(R.id.textViewContent);
                holder.imageView = convertView.findViewById(R.id.imageView);
            }
            else {
                holder = (ViewHolder)convertView.getTag();
            }
            holder.textViewTitle.setText(titles[position]);
            holder.textViewContent.setText(prices[position]);
            holder.imageView.setBackgroundResource(icons[position]);
            return convertView;
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">
    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">

    </ImageView>
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <TextView
            android:id="@+id/textViewTitle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="16sp"
            android:paddingTop="25dp">
        </TextView>
        <TextView
            android:id="@+id/textViewContent"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="11sp">
        </TextView>
    </LinearLayout>

</LinearLayout>