Go语言视频零基础入门到精通

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本帖讲解包含：


　　Toast--显示 View 的提示
　　Toast 显示一个 TextView
　　AlertDialog.Builder 提示对话框
　　购物列表--多选项 CheckBox 的应用
　　同意条款--CheckBox 的 isChecked 属性



Toast--显示 View 的提示
Toast 显示一个 ImageView
①新建工程


②在 drawable 文件夹中添加一副 png 图片：argon.png

③修改mainActivity.java 文件

package zyf.EX_Ctrl_3_B;

import

import

import

import

android.app.Activity;

android.os.Bundle;

android.widget.ImageView;

android.widget.Toast;

public class EX_Ctrl_3_B extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

/*设置主屏布局*/

setContentView(R.layout.main);

/*创建新Toast对象*/

Toast showImageToast=new Toast(this);

/*创建新ImageView对象*/

ImageView imageView=new ImageView(this);

/*从资源中获取图片*/

imageView.setImageResource(R.drawable.argon);

/*设置Toast上的View--(ImageView)*/

showImageToast.setView(imageView);

/*设置Toast显示时间*/

showImageToast.setDuration(Toast.LENGTH_LONG);

/*显示Toast*/

showImageToast.show();

}

}
复制代码④结果：




Toast 显示一个 Button


①新建工程
②修改 mainActivity.java 文件
package zyf.EX_Ctrl_3_B;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.Toast;

public class EX_Ctrl_3_B extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

/* 设置主屏布局 */

setContentView(R.layout.main);

/* 创建新Toast对象 */

Toast showImageToast = new Toast(this);

// /*新建Button对象*/

Button button = new Button(this);

button.setText("OK");

/* 设置Toast上的View--(Button) */

showImageToast.setView(button);

/* 设置Toast显示时间 */

showImageToast.setDuration(Toast.LENGTH_LONG);

/* 显示Toast */

showImageToast.show();

}

}
复制代码③结果：


Toast 显示一个 TextView


①新建工程
②修改 mainActivity.java 文件

package zyf.EX_Ctrl_3_B;

import android.app.Activity;

import android.os.Bundle;

import android.widget.TextView;

import android.widget.Toast;

public class EX_Ctrl_3_B extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

/* 设置主屏布局 */

setContentView(R.layout.main);

/* 创建新Toast对象 */

Toast showImageToast = new Toast(this);

/*新建TextView对象*/

TextView text=new TextView(this);

/*设置TextView内容*/

text.setText("显示在Toast中的TextView");

/* 设置Toast上的View--(TextView) */

showImageToast.setView(text);

/* 设置Toast显示时间 */

showImageToast.setDuration(Toast.LENGTH_LONG);

/* 显示Toast */

showImageToast.show();

}

}
复制代码
③结果


AlertDialog.Builder 提示对话框


①新建工程
②修改 mainActivity.java 文件
package zyf.EX_Ctrl_3_B;

import android.app.Activity;

import android.app.AlertDialog;

import android.os.Bundle;

public class EX_Ctrl_3_B extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

/* 设置主屏布局 */

setContentView(R.layout.main);

/*新建一个AlertDialog.Builder对象*/

AlertDialog.Builder my_ADialog =new AlertDialog.Builder(this);

/*设置标题*/

my_ADialog.setTitle("Android 提示");

/*设置显示消息*/

my_ADialog.setMessage("AlertDialog.Builder提示对话框消息!!");

/*显示*/

my_ADialog.show();

}

}
复制代码③结果




同意条款
CheckBox 的 isChecked 属性
①创建新工程
②在 string.xml 中添加字符串

<?xml version="1.0" encoding="utf-8"?>

<resources>

<string name="app_name">Ex_Ctrl_4</string>

<string name="advice">请勾选我同意</string>

<string name="accept">您已接受同意！！</string>

<string name="Notaccept">您未同意！！</string>

<string name="allOK">全部许可</string>

</resources>
复制代码
③修改 main.xml 布局，添加 UI 元素
<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

androidrientation="vertical"

android:layout_width="fill_parent"



android:layout_height="fill_parent"



>



<TextView

android:layout_height="wrap_content"

android:layout_width="fill_parent"

android:id="@+id/TextView_Guide"

android:textSize="25px" android:text="@string/advice"></TextView>

<TextView

android:layout_height="wrap_content"

android:layout_width="fill_parent"

android:id="@+id/TextView_youChoiceShow"

android:textSize="25px"></TextView>

<CheckBox

android:layout_height="wrap_content"

android:layout_marginTop="100px"

android:layout_marginLeft="90px"

android:id="@+id/CheckBox_Accept" android:layout_width="120px"></CheckBox>

<Button

android:layout_height="wrap_content"

android:layout_marginLeft="90px"

android:id="@+id/Button_OK"

android:text="确定"

android:layout_width="90px"></Button>

</LinearLayout>
复制代码
④修改 mainActivity.java 文件
package zyf.Ex_Ctrl_4;

import

import

import

import

import

import

import

android.app.Activity;

android.graphics.Color;

android.os.Bundle;

android.view.View;

android.widget.Button;

android.widget.CheckBox;

android.widget.TextView;

public class Ex_Ctrl_4 extends Activity {

/** Called when the activity is first created. */

private TextView showAdvice,yourChoiceshow;

private CheckBox iAccept;

private Button ok;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);





/*findViewById()从资源ID获取资源对象*/

showAdvice=(TextView)findViewById(R.id.TextView_Guide);

yourChoiceshow=(TextView)findViewById(R.id.TextView_youChoiceShow);

iAccept=(CheckBox)findViewById(R.id.CheckBox_Accept);

ok=(Button)findViewById(R.id.Button_OK);





/*获取XML中字符串*/

CharSequence titleString=getString(R.string.allOK);

/*设置复选框标题*/

iAccept.setHint(titleString);

/*设置复选框标题字体颜色*/

iAccept.setHintTextColor(Color.RED);

/*将CheckBox设置成未选中*/

iAccept.setChecked(false);

/*将Button设置成不可选*/

ok.setEnabled(false);

iAccept.setOnClickListener(new CheckBox.OnClickListener(){





@Override

public void onClick(View v) {

// TODO Auto-generated method stub

if(iAccept.isChecked()){



ok.setEnabled(true);

yourChoiceshow.setText(R.string.accept);

}else{

ok.setEnabled(false);

yourChoiceshow.setText(R.string.Notaccept);

}

}





});

ok.setOnClickListener(new Button.OnClickListener(){





@Override

public void onClick(View v) {

// TODO Auto-generated method stub

if(iAccept.isChecked()){

showAdvice.setText(R.string.accept);

}

}

});

}

}
复制代码结果：



购物列表

多选项 CheckBox 的应用


①新建工程
②在 string.xml 中添加字符串
<?xml version="1.0" encoding="utf-8"?>

<resources>

<string name="app_name">Ex_Ctrl_5</string>

<string name="shoopingList_TextView_text">网上购物商品清单</string>

<string name="yourChocieWoods_text">您选择购买的商品：</string>

<string name="woods_Text_MP4">纽曼MP4</string>

<string name="woods_Text_musicCD">Beyond乐队CD</string>

<string name="woods_Text_book">Android程序员指南</string>

</resources>
复制代码
③修改 main.xml 布局，添加 UI 元素
<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

>

<TextView

android:layout_height="wrap_content"

android:layout_width="fill_parent"

android:id="@+id/TextView_shoppingList"

android:text="@string/shoopingList_TextView_text"

android:textSize="25px"></TextView>

<CheckBox

android:layout_height="wrap_content"

android:id="@+id/CheckBox_MP4"

android:text="@string/woods_Text_MP4"

android:layout_width="180px"></CheckBox>

<CheckBox

android:layout_height="wrap_content"

android:text="@string/woods_Text_musicCD"

android:id="@+id/CheckBox_musicCD"

android:layout_width="180px"></CheckBox>

<CheckBox

android:layout_height="wrap_content"

android:text="@string/woods_Text_book"



android:id="@+id/CheckBox_book"

android:layout_width="180px"></CheckBox>

<TextView

android:layout_height="wrap_content"

android:layout_width="fill_parent"

android:id="@+id/TextView_yourChoice"

android:text="@string/yourChocieWoods_text"

android:textSize="20px"></TextView>

<TextView

android:layout_height="wrap_content"

android:id="@+id/TextView_yourWoodsList"

android:layout_width="fill_parent"

android:textSize="20px"></TextView>

</LinearLayout>
复制代码
④修改 mainActivity.java，添加逻辑判断
package zyf.Ex_Ctrl_5;

import

import

import

import

import

import

android.app.Activity;

android.os.Bundle;

android.widget.CheckBox;

android.widget.CompoundButton;

android.widget.TextView;

android.widget.CompoundButton.OnCheckedChangeListener;

public class Ex_Ctrl_5 extends Activity {

/** Called when the activity is first created. */

private TextView showyourChoice_TextView;

private CheckBox mp4_CheckBox, musicCD_CheckBox, book_CheckBox;

private String showinfo;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

/* findViewById()从XML中获取资源对象 */

showyourChoice_TextView=(TextView)findViewById(R.id.TextView_yourWoodsList);

mp4_CheckBox = (CheckBox) findViewById(R.id.CheckBox_MP4);

musicCD_CheckBox = (CheckBox) findViewById(R.id.CheckBox_musicCD);

book_CheckBox = (CheckBox) findViewById(R.id.CheckBox_book);

/* 为三个CheckBox设置选择状态改变事件监听器 */

mp4_CheckBox.setOnCheckedChangeListener(CheckedChangeListener);

musicCD_CheckBox.setOnCheckedChangeListener(CheckedChangeListener);

book_CheckBox.setOnCheckedChangeListener(CheckedChangeListener);

/* 从XML中获取显示信息String */

showinfo = getString(R.string.yourChocieWoods_text);

}

/* 内部接口实现 */



private OnCheckedChangeListener CheckedChangeListener = new

OnCheckedChangeListener() {

@Override

public void onCheckedChanged(CompoundButton buttonView,

boolean isChecked) {

// TODO Auto-generated method stub

/* 处理选中状态改变事件，动态显示选择结果 */

if (mp4_CheckBox.isChecked()) {

showinfo = getString(R.string.woods_Text_MP4) + "\n";

showString();

} else if (musicCD_CheckBox.isChecked()) {

showinfo = getString(R.string.woods_Text_musicCD) + "\n";

showString();

} else if (book_CheckBox.isChecked()) {

showinfo = getString(R.string.woods_Text_book) + "\n";

showString();

}

if (mp4_CheckBox.isChecked() && musicCD_CheckBox.isChecked()) {

showinfo = getString(R.string.woods_Text_MP4) + "\n"

+ getString(R.string.woods_Text_musicCD) + "\n";

showString();

} else if (mp4_CheckBox.isChecked() && book_CheckBox.isChecked()) {

showinfo = getString(R.string.woods_Text_MP4) + "\n"

+ getString(R.string.woods_Text_book) + "\n";

showString();

} else if (musicCD_CheckBox.isChecked()

&& book_CheckBox.isChecked()) {

showinfo = getString(R.string.woods_Text_musicCD) + "\n"

+ getString(R.string.woods_Text_book) + "\n";

showString();

}

if (mp4_CheckBox.isChecked() && musicCD_CheckBox.isChecked()

&& book_CheckBox.isChecked()) {

showinfo = getString(R.string.woods_Text_MP4) + "\n"



+ getString(R.string.woods_Text_musicCD) + "\n"

+ getString(R.string.woods_Text_book) + "\n";

showString();

}

if (mp4_CheckBox.isChecked() == false

&& musicCD_CheckBox.isChecked() == false

&& book_CheckBox.isChecked() == false) {

showyourChoice_TextView.setText("");

}

}

public void showString() {

showyourChoice_TextView.setText(showinfo);

}

};

}
复制代码

结果：