安卓5~6
1.按模拟器上返回键，实现对话框弹出“是否退出应用程序”，如果选择是，退出，选择否，不退出
package com.example.chap03;
import androidx.appcompat.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 dialog;
AlertDialog.Builder builder=new AlertDialog.Builder(this)
.setTitle("普通对话框")
.setIcon(R.mipmap.ic_launcher)
.setMessage("是否确定退出应用：")
.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();
}
});
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"
tools:context=".MainActivity"
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="20dp"
android:textSize="20sp"
android:textColor="#474141"
android:textStyle="bold"/>
<Button
android:id="@+id/bt_1"
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"
android:textSize="20sp"
android:textStyle="bold"
android:textColor="#474141"/>
</LinearLayout>
package com.example.homework8;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.content.DialogInterface;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import java.util.Locale;
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private TextView textView;
final String [] sexs=new String[]{"男","女"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewById(R.id.bt_1).setOnClickListener(this);
textView=(TextView) findViewById(R.id.tv_1);
}
public void onClick(View view){
AlertDialog dialog;
AlertDialog.Builder builder=new AlertDialog.Builder(this);
builder.setTitle("请选择你的性别：");
builder.setIcon(R.mipmap.ic_launcher);
builder.setSingleChoiceItems(sexs, 1, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(MainActivity.this,"您选择的是："+sexs[which],Toast.LENGTH_LONG).show();
dialog.dismiss();
}
});
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(MainActivity.this,"您选择了"+sexs[which],Toast.LENGTH_LONG).show();
dialog.dismiss();
}
})
.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
dialog=builder.create();
dialog.show();
}
}
3.实现如下布局界面
<?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=".MainActivity"
android:background="#25FA2A"
android:layout_margin="5dp">
<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:textColor="#F81606"
android:textSize="20sp"
android:textStyle="italic"
android:gravity="center"
android:layout_marginTop="20dp"/>
<Button
android:id="@+id/bu_1"
android:layout_width="360dp"
android:layout_height="wrap_content"
android:text="2.按钮"
android:textColor="#F81606"
android:textSize="20sp"
android:textStyle="bold"
android:layout_centerHorizontal="true"
android:layout_below="@id/tv_1"
android:padding="10dp"/>
<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:textColorHint="#F81606"
android:textSize="20sp"
android:layout_below="@id/bu_1"
android:layout_alignStart="@id/bu_1"
android:layout_margin="5dp"
android:padding="10dp"/>
<RadioGroup
android:id="@+id/rg_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/et_1"
android:layout_alignLeft="@id/et_1"
android:orientation="horizontal"
android:padding="5dp">
<RadioButton
android:id="@+id/rb_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="4.男"
android:textSize="20sp"
android:textColor="#F81606" />
<RadioButton
android:id="@+id/rb_2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="女"
android:textSize="20sp"
android:textColor="#F81606" />
</RadioGroup>
<LinearLayout
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/ck_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="电脑"
android:textSize="20sp"
android:textColor="#F81606"
android:padding="5dp" />
<CheckBox
android:id="@+id/ck_2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="手机"
android:textSize="20sp"
android:textColor="#F81606"
android:padding="5dp"/>
</LinearLayout>
</RelativeLayout>
4.教材p76页 图3—17购物商城界面
activity_main.xml:
<?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" android:layout_width="match_parent" android:layout_height="50dp" android:text="购物商城" android:textColor="#E8E3E9" android:background="#C175CE" android:textSize="20sp" android:gravity="center"/> <ListView android:id="@+id/lv" android:layout_width="match_parent" android:layout_height="wrap_content"/> </LinearLayout>
list_item.xml:
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:padding="15dp"> <ImageView android:id="@+id/iv" android:layout_width="100dp" android:layout_height="80dp" android:layout_centerVertical="true"/> <RelativeLayout android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_marginLeft="10dp" android:layout_toRightOf="@id/iv"> <TextView android:id="@+id/title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="桌子" android:textSize="20sp" android:textColor="#4B4343"/> <TextView android:id="@+id/tv_p" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="价格" android:textSize="20sp" android:textColor="#F5A631" android:layout_below="@id/title" android:layout_marginTop="10dp"/> <TextView android:id="@+id/price" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="1800" android:textSize="20sp" android:textColor="#F5A631" android:layout_below="@id/title" android:layout_toRightOf="@id/tv_p" android:layout_marginTop="10dp"/> </RelativeLayout> </RelativeLayout>
package com.example.chap07;
import androidx.appcompat.app.AppCompatActivity;
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 AppCompatActivity {
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元","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 = (ListView) findViewById(R.id.lv);//初始化ListView控件
MyBaseAdapter myAdapter = new MyBaseAdapter();//创建一个Adapter实例
mListView.setAdapter(myAdapter);//设置Adapter
}
class MyBaseAdapter extends BaseAdapter{
@Override
public int getCount() { //获取item的总数
return titles.length; //返回ListView Item条目的总数
}
@Override
public Object getItem(int i) {
return titles[i]; //返回Item的数据对象
}
@Override
public long getItemId(int i) {
return i; //返回Item的id
}
//得到Item的View视图
@Override
public View getView(int i, View view, ViewGroup viewGroup) {
View view1= View.inflate(MainActivity.this,R.layout.list_item,null);
TextView title = (TextView)view1.findViewById(R.id.title);
TextView price = (TextView)view1.findViewById(R.id.price);
ImageView iv = (ImageView)view1.findViewById(R.id.iv);
title.setText(titles[i]);
price.setText(prices[i]);
iv.setBackgroundResource(icons[i]);
return view1;
}
}
}
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