安卓第五、六周作业
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 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("是否退出应用:")
.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int i) {
dialog.dismiss();
MainActivity.this.finish();
}
})
.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int i) {
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)
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; //implements View.OnClickListener public class MainActivity extends AppCompatActivity implements View.OnClickListener{ // private TextView textView; private int num=0; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.text62); findViewById(R.id.b_1).setOnClickListener(this); // textView =(TextView) findViewById(R.id.t_1); } 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"}, -1, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { num=i; } }) .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { if (num==0){ Toast.makeText(MainActivity.this,"你选择男",Toast.LENGTH_LONG).show(); }else { Toast.makeText(MainActivity.this,"你选择女",Toast.LENGTH_LONG).show(); } dialog.dismiss(); } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { dialog.dismiss(); } }); dialog=builder.create(); dialog.show(); } @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("是否退出应用:") .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { dialog.dismiss(); MainActivity.this.finish(); } }) .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)
<?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" android:background="#15E61E"> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="20dp" android:text="1.TextView显示的文本信息" android:gravity="center" android:textSize="20sp" android:textColor="#FF0000"/> <Button android:layout_width="370dp" android:layout_height="wrap_content" android:layout_gravity="center" android:text="2.按钮" android:textSize="20sp" android:textColor="#FF0000"/> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:text="3.编辑框:请输入信息" android:textSize="20sp" android:textColor="#FF0000"/> <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="男" android:textSize="20sp" android:textColor="#FF0000" /> <RadioButton android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="女" android:textSize="20sp" android:textColor="#FF0000"/> </RadioGroup> <RadioGroup android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <CheckBox android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="电脑" android:textSize="20sp" android:textColor="#FF0000"/> <CheckBox android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="手机" android:textSize="20sp" android:textColor="#FF0000"/> </RadioGroup> </LinearLayout>
4.教材p76页 图3—17购物商城界面
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <TextView android:id="@+id/tv_1" android:layout_width="match_parent" android:layout_height="60dp" android:text="购物商城" android:textColor="#FCF7F7" android:textSize="22sp" android:gravity="center" android:background="#FF5722"/> <ListView android:id="@+id/lv_1" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@+id/tv_1"/> </RelativeLayout>
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <ImageView android:id="@+id/image" android:layout_width="150dp" android:layout_height="150dp" android:layout_margin="1dp"/> <TextView android:id="@+id/tv_list" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="22sp" android:textColor="#000000" android:layout_marginTop="30dp" android:layout_toRightOf="@id/image" android:layout_marginLeft="15dp"/> <TextView android:id="@+id/tv_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="价格:" android:textSize="18sp" android:layout_below="@id/tv_list" android:layout_toRightOf="@id/image" android:layout_marginTop="15dp" android:layout_marginLeft="15dp"/> <TextView android:id="@+id/tv_price" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="18sp" android:layout_toRightOf="@id/tv_2" android:layout_below="@id/tv_list" android:layout_marginTop="15dp" android:layout_marginLeft="10dp"/> </RelativeLayout>
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.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.ListView; import android.widget.TextView; import android.widget.Toast; ////implements View.OnClickListener 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.text64); mListView = (ListView) findViewById(R.id.lv_1); //MyBaseAdapter mAdapter = new MyBaseAdapter(); mListView.setAdapter(new MyBaseAdapter()); } 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.text64_item, null); TextView title = view.findViewById(R.id.tv_list); TextView price = view.findViewById(R.id.tv_price); ImageView iv = view.findViewById(R.id.image); title.setText(titles[position]); price.setText(prices[position]); iv.setImageResource(icons[position]); return view; } } @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("是否退出应用:") .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { dialog.dismiss(); MainActivity.this.finish(); } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { dialog.dismiss(); } }); dialog=builder.create(); dialog.show(); } }