第五六周作业
一、 返回键实现对话框弹出是否退出应用程序
package itcast.cn; import android.app.AlertDialog; import android.content.DialogInterface; import android.os.Bundle; import android.app.Activity; public class Main2Activity extends Activity { protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main2); } public void onBackPressed(){ AlertDialog dialog; AlertDialog.Builder builder=new AlertDialog.Builder(this) .setTitle("普通对话框") .setIcon(R.drawable.ic_launcher_background) .setMessage("是否确定退出") .setPositiveButton("确定", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); Main2Activity.this.finish();} }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); dialog=builder.create(); dialog.show(); } }

二、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"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<Button
android:id="@+id/bt_1"
android:layout_width="wrap_content"
android:layout_height="100dp"
android:text="单选框"
android:gravity="center"
android:layout_marginTop="50dp"
android:layout_gravity="center">
</Button>
</LinearLayout>
package itcast.cn;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
public class Main2Activity extends Activity implements View.OnClickListener{
private int i=1;
private int i1[]={1,2};
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
findViewById(R.id.bt_1).setOnClickListener(this);
}
public void onClick(View v){
AlertDialog dialog;
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("你的性别是?");
builder.setSingleChoiceItems(new String[]{"女","男"},i,new DialogInterface.OnClickListener(){
public void onClick(DialogInterface dialog,int which){
i=which;
}
});
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
if (i==1){
Toast.makeText(Main2Activity.this,"你选择了男",Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(Main2Activity.this,"你选择了女",Toast.LENGTH_SHORT).show();
}
dialog.dismiss();
}
});
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
dialog = builder.create();
dialog.show();
}
}


三、实现如下布局界面
<?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:background="#00FF20"
android:orientation="vertical">
<TextView
android:layout_width="200dp"
android:layout_height="50dp"
android:text="1.TextView显示文本"
android:textSize="20dp"
android:gravity="center"
android:layout_marginTop="50dp"
android:layout_gravity="center"
android:textStyle="italic"
android:textColor="#C00000">
</TextView>
<Button
android:id="@+id/bt_1"
android:layout_width="250dp"
android:layout_height="50dp"
android:text="2.按钮"
android:textSize="25dp"
android:textColor="#C00000"
android:gravity="center"
android:layout_gravity="center">
</Button>
<EditText
android:layout_width="match_parent"
android:layout_height="50dp"
android:hint="3.编辑框:请输入信息"
android:textColorHint="#C00000"
android:layout_marginLeft="20dp"
android:textSize="25sp"
android:textStyle="bold">
</EditText>
<RadioGroup
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<RadioButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="4.男"
android:layout_marginLeft="20dp"
android:textSize="25dp"
android:textColor="#C00000">
</RadioButton>
<RadioButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textStyle="bold"
android:text="女"
android:textSize="25dp"
android:textColor="#C00000"></RadioButton>
</RadioGroup>
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="电脑"
android:layout_marginLeft="20dp"
android:textSize="25dp"
android:textColor="#C00000"></CheckBox>
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="手机"
android:layout_marginLeft="20dp"
android:textSize="25dp"
android:textColor="#C00000"></CheckBox>
</LinearLayout>

4.教材p76页 图3—17购物商城界面
package itcast.cn;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.ImageView;
public class Main2Activity extends Activity{
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/千克","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(Bundle savedInstancestate){
super.onCreate(savedInstancestate);
setContentView(R.layout.activity_main2);
mListView=(ListView)findViewById(R.id.lv);
MyBaseAdapter mAdapter =new MyBaseAdapter();
mListView.setAdapter(mAdapter);
}
class MyBaseAdapter extends BaseAdapter{
public int getCount(){
return titles.length;
}
public Object getItem(int position){
return titles[position];
}
public long getItemId(int position) {
return position;
}
public View getView(int position,View convertView,ViewGroup parent){
View view=View.inflate(Main2Activity.this,R.layout.activity_main3,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;
}
}
}
<?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="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="80dp"
android:gravity="center"
android:text="购物商城"
android:textColor="#CC0000"
android:textSize="40dp"
android:background="#33FFFF"></TextView>
<ListView
android:id="@+id/lv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"></ListView>
</LinearLayout>
<?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">
<ImageView
android:layout_width="200dp"
android:layout_height="200dp"
android:id="@+id/iv"
/>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_toRightOf="@id/iv"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/title"
android:layout_marginTop="50dp"
android:layout_marginLeft="15dp"
/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="价格:"
android:id="@+id/jg"
android:layout_below="@id/title"
android:layout_marginTop="50dp"
android:layout_marginLeft="15dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/price"
android:layout_toRightOf="@id/jg"
android:layout_below="@id/title"
android:layout_marginTop="50dp"
android:layout_marginLeft="15dp"/>
</RelativeLayout>
</LinearLayout>




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