9.18第三次android作业
1.返回键实现对话框弹出是否退出应用程序
package com.example.name; import android.os.Bundle; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.view.Menu; import android.view.View; import android.widget.Button; import android.widget.Toast; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); // 获取到btn2按钮 Button btn2 = (Button) findViewById(R.id.btn_2);// 低版本的SDK必须强制类型转换 // 设置监听事件 btn2.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Toast.makeText(MainActivity.this, "按钮2被点击", 0).show();// 第一个参数是上线文参数,表示要在哪里显示 } }); } public void click1(View v) { Toast.makeText(this, "按钮1被点击", 0).show(); } // 当点击返回按钮时 public void onBackPressed() { AlertDialog dialog; AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setIcon(R.drawable.ic_launcher); builder.setTitle("普通对话框"); 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(); MainActivity.this.finish();// 主窗口关闭 } }); builder.setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); dialog = builder.create(); dialog.show(); } } <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" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/hello_world" /> <Button android:id="@+id/btn_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="click1" android:text="按钮1" /> <Button android:id="@+id/btn_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="按钮2" /> </LinearLayout>
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)
import junit.framework.Test; import android.os.Bundle; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.TextView; public class MainActivity extends Activity implements OnClickListener{ private TextView textView; private int[] textSizeArr = {10,20}; int textSize = 1;//选中项的下标,从0开始 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //设置Button监听事件 findViewById(R.id.bt).setOnClickListener(this); textView = (TextView) findViewById(R.id.bt); } @Override public void onClick(View v) { AlertDialog dialog; AlertDialog.Builder builder = new AlertDialog.Builder(this) .setTitle("选择性别") //设置标题 .setIcon(R.drawable.ic_launcher) .setSingleChoiceItems(new String[]{"男", "女"}, 1,new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int which) { textSize = which; } }) .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { //为TextView设置在单选对话框中选择的字体大小 textView.setTextSize(textSizeArr[textSize]);//字号设置为你单选按钮选中的那项的下标,数组中对应的值 dialog.dismiss(); //关闭对话框 } })//添加“确定”按钮 .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); dialog = builder.create(); dialog.show(); } } <RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="你的性别是" android:layout_marginTop="10dp" android:textSize="20sp" /> <Button android:id="@+id/bt" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="选择性别" android:layout_marginTop="20dp" android:layout_gravity="center"/> </RelativeLayout>
3.
<?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="#0DFF18"> <TextView android:layout_width="match_parent" android:layout_height="40dp" android:text="1.TextView显示的文本信息" android:textSize="29sp" android:layout_marginLeft="40dp" android:layout_marginRight="20dp" android:layout_marginTop="30dp" android:textColor="#FF0000" /> <Button android:layout_width="match_parent" android:layout_height="60dp" android:text="2.按钮" android:textSize="30sp" android:layout_marginLeft="20dp" android:layout_marginRight="20dp" android:layout_marginTop="90dp" android:textColor="#FF0000"/> <EditText android:layout_width="match_parent" android:layout_height="60dp" android:text="3.编辑框:请输入信息" android:textSize="30sp" android:layout_marginLeft="20dp" android:layout_marginRight="20dp" android:layout_marginTop="180dp" android:textColor="#FF0000"/> <RadioGroup android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="20dp" android:layout_marginRight="20dp" android:orientation="horizontal"> <RadioButton android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="4.男" android:textSize="30sp" android:textColor="#FF0000" android:layout_marginTop="250dp"/> <RadioButton android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="女" android:textSize="30sp" android:textColor="#FF0000" android:layout_marginTop="250dp" /> </RadioGroup> <CheckBox android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="电脑" android:textColor="#FF0000" android:textSize="30sp" android:layout_marginLeft="20dp" android:layout_marginRight="20dp" android:layout_marginTop="300dp"/> <CheckBox android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="手机" android:textColor="#FF0000" android:textSize="30sp" android:layout_marginLeft="20dp" android:layout_marginRight="20dp" android:layout_marginTop="340dp"/> </RelativeLayout>
4.
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.ListAdapter; import android.widget.ListView; import android.widget.TextView; 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/kg", "300元", "350元", "10/kg", "280元"}; 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); MyBaseAdapter mAdapter = new MyBaseAdapter(); mListView.setAdapter( mAdapter); } class MyBaseAdapter extends BaseAdapter { @Override public int getCount() { return titles.length; } @Override public Object getItem(int i) { return titles[i]; } @Override public long getItemId(int i) { return i; } @Override public View getView(int i, View view, ViewGroup viewGroup) { view = View.inflate(MainActivity.this, R.layout.item, null); TextView title = view.findViewById(R.id.name_shop); TextView price = view.findViewById(R.id.price_shop); ImageView iv = view.findViewById(R.id.shop_iv); title.setText(titles[i]); price.setText(prices[i]); iv.setImageResource(icons[i]); return view; } } }
<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"> <TextView android:id="@+id/gouqu" android:layout_width="match_parent" android:layout_height="50dp" android:background="#E91E63" android:text="购物商城" android:textSize="35sp" android:gravity="center" /> <ListView android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/lv" android:layout_below="@id/gouqu"/> </RelativeLayout>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <ImageView android:layout_width="200dp" android:layout_height="200dp" android:id="@+id/shop_iv" /> <RelativeLayout android:layout_width="match_parent" android:layout_height="match_parent" android:layout_toRightOf="@id/shop_iv" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/name_shop" 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/pr" android:layout_below="@id/name_shop" android:layout_marginTop="50dp" android:layout_marginLeft="15dp"/> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/price_shop" android:layout_toRightOf="@id/pr" android:layout_below="@id/name_shop" android:layout_marginTop="50dp" android:layout_marginLeft="15dp"/> </RelativeLayout> </RelativeLayout>