安卓3个练习题

1、实现随机生成一个6位的整数，并输出由该数的6位数字组成的最小数和最大数

layout文件：

<?xml version="1.0" encoding="utf-8"?>
<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: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="com.hanqi.testapp2.PractiseActivity2"
android:orientation="vertical">

<TextView
android:layout_width="match_parent"
android:layout_height="80dp"
android:id="@+id/tv1"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/btt"
android:text="随机生成"
android:onClick="btt_onClick"/>
</LinearLayout>

java类代码：

package com.hanqi.testapp2;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import java.util.Arrays;

public class PractiseActivity2 extends AppCompatActivity {

TextView tv1;
Button btt;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_practise2);
tv1 = (TextView)findViewById(R.id.tv1);
btt = (Button)findViewById(R.id.btt);
}
public void btt_onClick(View v)
{
//根据数组个数循环
int[] ary = new int[6];
String result = "";
int max = 0;
int min = 9;

for(int i = 0; i < 6; i++){
ary[i] = (int) (Math.random()*10);
//首位数字不能为0
while(ary[0] == 0)
{
ary[0] = (int) (Math.random()*10);
}
result += ary[i];
//取出最大最小值，用于组装最大最小值
max = Math.max(ary[i], max);
min = Math.min(ary[i], min);
}

Arrays.sort(ary);
//最大值
String maxResult = "";
for(int i = 5; i >= 0; i--){
maxResult += ary[i];
}
//最小值
String minResult = "";
for(int i : ary){
minResult += i;
}
tv1.setText(result+"\n"+minResult+"\n"+maxResult);
}
}

效果为：





2、写出实现如图所示的对话框的代码。



layout文件：

<?xml version="1.0" encoding="utf-8"?>
<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="com.hanqi.testapp2.PractiseActivity3">

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="bt_1_onClick"
android:text="提示"/>
</RelativeLayout>

java类代码：

package com.hanqi.testapp2;

import android.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

public class PractiseActivity3 extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_practise3);
}
public void bt_1_onClick(View v)
{
new AlertDialog.Builder(this)
.setTitle("提示")
.setMessage("确定要删除吗？\n要删除，请点击“是”。")
.setPositiveButton("否",null)
.setNegativeButton("是",null)
.show();
}
}

效果图：



3、设计界面如下图如示，在编辑框中只接受电话号码，实现“拨打电话”和“发送短信”的功能。



layout文件：

<?xml version="1.0" encoding="utf-8"?>
<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: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="com.hanqi.testapp2.PractiseActivity3"
android:orientation="vertical">

<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="请输入电话号码"/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="phone"
android:id="@+id/et1_phone"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="拨出此号码"
android:onClick="bt_bd_onClick"/>
<Button
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="向此号码发送短信"
android:onClick="bt_fs_onClick"/>
</LinearLayout>
</LinearLayout>

java类代码：

package com.hanqi.testapp2;

import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class PractiseActivity3 extends AppCompatActivity {

EditText et1_phone;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_practise3);
et1_phone = (EditText)findViewById(R.id.et1_phone);
}
public void bt_bd_onClick(View v)
{
String phone = getPhone();
if (phone == null) return;
Intent intent = new Intent(Intent.ACTION_DIAL);
Uri uri = Uri.parse("tel:"+phone);
intent.setData(uri);
startActivity(intent);
}
public String getPhone()
{
String phone = et1_phone.getText().toString().trim();
if (phone.length()==0)
{
Toast.makeText(PractiseActivity3.this, "请正确填写电话号码", Toast.LENGTH_SHORT).show();
return null;
}
return phone;
}
public String getMessage()
{
String message = et1_phone.getText().toString().trim();
if (message.length()==0)
{
Toast.makeText(PractiseActivity3.this, "请正确填写电话号码", Toast.LENGTH_SHORT).show();
return null;
}
return message;
}
public void bt_fs_onClick(View v)
{
String message = getMessage();
if (message == null) return;
Uri smsToUri = Uri.parse("smsto:message");
Intent intent = new Intent(Intent.ACTION_SENDTO, smsToUri);
intent.setData(Uri.parse("smsto:"+message));
startActivity(intent);
}
}

效果图为：