第三次作业
1.返回键实现对话框弹出是否退出应用程序
package com.example.myapplication;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.content.DialogInterface;
import android.os.Bundle;
public class CommonDialog extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_common_dialog);
}
@Override
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("是否退出应用程序");
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
CommonDialog.this.finish();
}
});
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
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"
tools:context=".SingleChoiceDialog"
android:orientation="vertical">
<TextView
android:id="@+id/tv_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="单选对话框"
android:gravity="center"
android:layout_marginTop="10dp"
android:textSize="20sp"
android:textStyle="bold"
android:textColor="#000000"
/>
<Button
android:id="@+id/btn_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="选择性别："
android:textSize="20sp"
android:textStyle="bold"
android:textColor="#000000"
android:layout_marginTop="20dp"
android:layout_gravity="center"
/>
</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;
import android.widget.Toast;
public class SingleChoiceDialog extends AppCompatActivity implements View.OnClickListener {
private TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_single_choice_dialog);
findViewById(R.id.btn_1).setOnClickListener(this);
textView=(TextView)findViewById(R.id.tv_1);
}
@Override
public void onClick(View view) {
AlertDialog dialog ;
AlertDialog.Builder builder=new AlertDialog.Builder(this);
builder.setTitle("性别：");
builder.setIcon(R.mipmap.ic_launcher);
final String[] sexs = new String[]{"男","女"};
builder.setSingleChoiceItems(sexs, 0, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(SingleChoiceDialog.this, "您选择了: " + sexs[which], Toast.LENGTH_LONG).show();
}
});
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(SingleChoiceDialog.this, "你选择了男", Toast.LENGTH_LONG).show();
}
});
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
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"?>
<RelativeLayout
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:background="#31B404"
android:layout_margin="2dp"
tools:context=".MyLayout">
<TextView
android:id="@+id/tv_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="1.TextView显示文本信息"
android:textSize="20sp"
android:textColor="#FF0000"
android:textStyle="bold"
android:gravity="center"
android:layout_marginTop="10dp"
/>
<Button
android:id="@+id/btn_1"
android:layout_width="350dp"
android:layout_height="wrap_content"
android:text="2.按钮"
android:textSize="20sp"
android:textColor="#FF0000"
android:textStyle="bold"
android:padding="5dp"
android:layout_centerHorizontal="true"
android:layout_below="@+id/tv_1"
/>
<EditText
android:id="@+id/et_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="3.编辑框：请输入信息"
android:textSize="20sp"
android:textColorHint="#FF0000"
android:layout_below="@id/btn_1"
android:layout_alignStart="@id/btn_1"
android:layout_margin="5dp"
/>
<RadioGroup
android:id="@+id/rg_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_below="@id/et_1"
android:layout_alignLeft="@id/et_1"
>
<RadioButton
android:id="@+id/rb_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="4.男"
android:textColor="#FF0000"
android:textSize="20sp"
android:textStyle="bold"
/>
<RadioButton
android:id="@+id/rb_2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="女"
android:textColor="#FF0000"
android:textSize="20sp"
android:textStyle="bold"
/>
</RadioGroup>
<LinearLayout
android:id="@+id/ll_1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:layout_below="@id/rg_1"
android:layout_alignLeft="@id/rg_1">
<CheckBox
android:id="@+id/cb_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="电脑"
android:textSize="20sp"
/>
<CheckBox
android:id="@+id/cb_2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="手机"
android:textSize="20sp"/>
</LinearLayout>
</RelativeLayout>
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"
tools:context=".MainActivity"
android:orientation="vertical">
<TextView
android:id="@+id/tv_1"
android:layout_width="match_parent"
android:layout_height="45dp"
android:text="购物商城"
android:textSize="18sp"
android:textColor="#000000"
android:background="#FF8F03"
android:gravity="center"/>
<ListView
android:id="@+id/lv_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
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"
tools:context=".List_item"
android:padding="16dp">
<ImageView
android:id="@+id/iv"
android:layout_width="120dp"
android:layout_height="90dp"
android:layout_centerVertical="true"/>
<RelativeLayout
android:id="@+id/rl_1"
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="wrap_content"
android:layout_height="wrap_content"
android:text="桌子"
android:textColor="#000000"
android:textSize="20sp"/>
<TextView
android:id="@+id/tv_price"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="价格"
android:textColor="#FF8F03"
android:textSize="20sp"
android:layout_marginTop="10dp"
android:layout_below="@id/title"/>
<TextView
android:id="@+id/price"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="1000"
android:textSize="20sp"
android:textColor="#FF8F03"
android:layout_toRightOf="@id/tv_price"
android:layout_marginTop="10dp"
android:layout_below="@+id/title"/>
</RelativeLayout>
</RelativeLayout>
package com.example.andoidtest;
import android.app.Activity;
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;
public class MainActivity extends Activity {
private ListView mListView;
//商品名称与价格数据集合
private String [] titles={"桌子","苹果","蛋糕","线衣","猕猴桃","围巾"};
private String [] prices={"1800","10元/kg","300元","350元","10元/kg","280元"};
//图片数据集合
private int [] icons={R.drawable.table,R.drawable.apple,R.drawable.cake,R.drawable.wireclothes,R.drawable.kiwifruit,R.drawable.scarf};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mListView=findViewById(R.id.lv_1);
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.activity_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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