【攻克Android(安卓)(6)】事件

本文围绕以下两个部分展开：

一、“办公自动化”案例
二、“BMI（体重指数）”案例

附补充代码

一、“办公自动化”案例

实现以下效果：

1. 在 styles.xml(v21) 中，实现状态栏变蓝。

 <?xml version="1.0" encoding="utf-8"?>   <resources>   <!--隐藏标题栏-->   <style name="AppTheme" parent="android:Theme.Material.Light.NoActionBar">     <item name="android:colorPrimaryDark">@android:color/holo_blue_dark</item>     <item name="android:colorPrimary">@android:color/holo_blue_light</item>   </style>   </resources>

2. 在 strings.xml 中，定义字符串。

 <resources>     <string name="app_name">Event</string>        <string name="oa">办公自动化</string>     <string name="phone_hint">请输入手机号</string>     <string name="password_hint">请输入密码</string>     <string name="cb_password">显示密码</string>     <string name="btn_login">登录</string>     <string name="forget_password">忘记密码</string>        <string name="action_settings">Settings</string>   </resources>

3. 在主界面（activity_main.xml）中，设计布局。

 <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"                      tools:context=".MainActivity">        <TextView         android:id="@+id/tvOA"         android:text="@string/oa"         android:gravity="center"         android:textSize="30sp"         android:textColor="@android:color/white"         android:background="@android:color/holo_blue_light"         android:layout_width="match_parent"         android:layout_height="150dp"/>     <RelativeLayout         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:layout_below="@+id/tvOA"         android:paddingLeft="@dimen/activity_horizontal_margin"         android:paddingRight="@dimen/activity_horizontal_margin"         android:paddingTop="@dimen/activity_vertical_margin"         android:paddingBottom="@dimen/activity_vertical_margin">       <EditText           android:id="@+id/txtPhone"           android:layout_width="match_parent"           android:layout_height="wrap_content"           android:hint="@string/phone_hint"           android:inputType="phone"           android:maxLength="11"/>          <EditText           android:id="@+id/txtPassword"           android:layout_width="match_parent"           android:layout_height="wrap_content"           android:layout_below="@+id/txtPhone"           android:hint="@string/password_hint"           android:inputType="textPassword"/>              <CheckBox           android:id="@+id/cbPassword"           android:layout_width="wrap_content"           android:layout_height="wrap_content"           android:text="@string/cb_password"           android:layout_below="@+id/txtPassword"/>          <Button           android:id="@+id/btnLogin"           android:layout_width="wrap_content"           android:layout_height="wrap_content"           android:layout_below="@+id/txtPassword"           android:layout_alignParentRight="true"           android:onClick="onClick"           android:text="@string/btn_login"/>          <Button           android:id="@+id/btnForgetPassword"           android:layout_width="wrap_content"           android:layout_height="wrap_content"           android:layout_below="@+id/btnLogin"           android:layout_alignParentRight="true"           android:onClick="onClick"           android:text="@string/forget_password"           style="@android:style/Widget.Material.Button.Borderless"/>        </RelativeLayout>      </RelativeLayout>

4. 在主活动（MainActivity）中，写事件。

 package com.xiangdong.event;     import android.app.Activity;   import android.os.Bundle;   import android.text.method.HideReturnsTransformationMethod;   import android.text.method.PasswordTransformationMethod;   import android.view.Menu;   import android.view.MenuItem;   import android.view.View;   import android.widget.CheckBox;   import android.widget.CompoundButton;   import android.widget.EditText;   import android.widget.Toast;         public class MainActivity extends Activity {       // 1. 声明控件/声明变量 (定义3个即可。输入手机号、输入密码、显示密码)(登录和忘记密码，在代码中写)     private EditText txtPhone;       private EditText txtPassword;       private CheckBox cbPassword;          @Override       protected void onCreate(Bundle savedInstanceState) {           super.onCreate(savedInstanceState);           setContentView(R.layout.activity_main);              // 2. 初始化控件           txtPhone = (EditText) findViewById(R.id.txtPhone);           txtPassword = (EditText) findViewById(R.id.txtPassword);           cbPassword = (CheckBox) findViewById(R.id.cbPassword);              // 3. 注册 CheckBox 状态改变的事件（选中：显示密码 或 未选中：隐藏密码）           cbPassword.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {               @Override               public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {                  // 事件处理代码                   if(isChecked){                       // 如果选中则显示密码 (隐藏星号)                       txtPassword.setTransformationMethod(                               HideReturnsTransformationMethod.getInstance());                   } else {                       // 否则隐藏密码 （密码转换成星号）                       txtPassword.setTransformationMethod(                               PasswordTransformationMethod.getInstance()                       );                   }               }           });       }       // 按钮事件（点击事件）       public void onClick(View view){           //不同的按钮匹配不同的事件。可以用switch，也可以用if-else           switch (view.getId()){               case R.id.btnLogin:                   //登录 流程                   String phone = txtPhone.getText().toString();                   String password = txtPassword.getText().toString();                   //格式化输出值 (好处：当值多的时候，不用使用“ ”+的形式)                   String text = String.format("Phone:%s\nPassword:%s",phone,password);                   Toast.makeText(this,text,Toast.LENGTH_SHORT).show();                   break;               case R.id.btnForgetPassword:                   //忘记密码 流程                   break;           }       }          @Override       public boolean onCreateOptionsMenu(Menu menu) {           // Inflate the menu; this adds items to the action bar if it is present.           getMenuInflater().inflate(R.menu.menu_main, menu);           return true;       }          @Override       public boolean onOptionsItemSelected(MenuItem item) {           // Handle action bar item clicks here. The action bar will           // automatically handle clicks on the Home/Up button, so long           // as you specify a parent activity in AndroidManifest.xml.           int id = item.getItemId();              //noinspection SimplifiableIfStatement           if (id == R.id.action_settings) {               return true;           }              return super.onOptionsItemSelected(item);       }   }

二、“BMI（体重指数）”案例

实现以下效果：

1. 在 styles.xml(v21) 中，实现状态栏变蓝。

2. 在 strings.xml 中，定义字符串。

 <resources>     <string name="app_name">Bmi</string>        <string name="action_settings">Settings</string>     <string name="bmi">BMI(体重指数)</string>     <string name="male">男</string>     <string name="female">女</string>     <string name="calWeight">计算标准体重</string>     <string name="standWeight">标准体重:</string>     <string name="scope">体重的合理范围:</string>     <string name="weight_hint">输入您的体重(kg)</string>     <string name="height_hint">输入您的身高(cm)</string>     <string name="about">关于</string>     <string name="aboutContent" formatted="false">           世界卫生组织计算标准体重的方法:\n\n           男性:(身高cm - 80) × 70% = 标准体重\n           女性:(身高cm - 70) × 60% = 标准体重\n\n\n           标准体重正负 10% 为正常体重\n           标准体重正负 10% ~ 20% 为体重过重或过轻\n           标准体重正负 20% 以上为肥胖或体重不足     </string>   </resources>

3. 在主界面（activity_main.xml）中，设计布局。

 <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"                   tools:context=".MainActivity">        <TextView         android:id="@+id/tvBmi"         android:text="@string/bmi"         android:gravity="center"         android:textSize="30sp"         android:textColor="@android:color/white"         android:background="@android:color/holo_blue_light"         android:layout_width="match_parent"         android:layout_height="100dp"/>     <RelativeLayout         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:layout_below="@+id/tvBmi"         android:paddingLeft="@dimen/activity_horizontal_margin"         android:paddingRight="@dimen/activity_horizontal_margin"         android:paddingTop="@dimen/activity_vertical_margin"         android:paddingBottom="@dimen/activity_vertical_margin">          <RadioGroup           android:id="@+id/sexGroup"           android:layout_width="match_parent"           android:layout_height="wrap_content"           android:orientation="horizontal">            <RadioButton             android:id="@+id/rbMale"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_weight="1"             android:checked="true"             android:text="@string/male"/>            <RadioButton             android:id="@+id/rbFemale"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_weight="1"             android:text="@string/female"/>       </RadioGroup>          <EditText           android:id="@+id/txtHeight"           android:layout_width="match_parent"           android:layout_height="wrap_content"           android:layout_below="@+id/sexGroup"           android:hint="@string/height_hint"           android:inputType="number"/>          <EditText           android:id="@+id/txtWeight"           android:layout_width="match_parent"           android:layout_height="wrap_content"           android:layout_below="@+id/txtHeight"           android:inputType="numberDecimal"           android:hint="@string/weight_hint"/>          <Button           android:id="@+id/btnCalWeight"           android:layout_width="wrap_content"           android:layout_height="wrap_content"           android:layout_below="@+id/txtWeight"           android:onClick="onClick"           android:text="@string/calWeight"/>          <Button           android:id="@+id/btnAbout"           android:layout_width="wrap_content"           android:layout_height="wrap_content"           android:layout_below="@+id/txtWeight"           android:layout_toRightOf="@+id/btnCalWeight"           android:onClick="onClick"           android:text="@string/about"/>          <TextView           android:id="@+id/tvScope"           android:layout_width="wrap_content"           android:layout_height="wrap_content"           android:layout_below="@+id/btnCalWeight"           android:text="@string/scope"           android:visibility="gone"/>          <TextView           android:id="@+id/tvAboutContent"           android:layout_width="wrap_content"           android:layout_height="wrap_content"           android:layout_alignParentBottom="true"           android:layout_centerHorizontal="true"           android:text="@string/aboutContent"           android:visibility="gone"/>        </RelativeLayout>    </RelativeLayout>

4. 在主活动（MainActivity）中，写事件。

 package com.xiangdong.bmi;      import android.app.Activity;   import android.graphics.Color;   import android.os.Bundle;   import android.view.Menu;   import android.view.MenuItem;   import android.view.View;   import android.widget.EditText;   import android.widget.RadioButton;   import android.widget.TextView;   import android.widget.Toast;         public class MainActivity extends Activity {          @Override       protected void onCreate(Bundle savedInstanceState) {           super.onCreate(savedInstanceState);           setContentView(R.layout.activity_main);       }          public void onClick(View view) {           switch (view.getId()) {               case R.id.btnCalWeight:                   String sheight = this.getEditText(R.id.txtHeight);                   String sweight = this.getEditText(R.id.txtWeight);                      // 验证 输入的性别/身高 是否有效                   if (sheight == null || sheight.trim().length() == 0) {                       Toast.makeText(this, R.string.height_hint, Toast.LENGTH_SHORT).show();                       return;                   } else if (sweight == null || sweight.trim().length() == 0) {                       sweight = "0";                   }                      // System.out.println(sex + " " + sheight + " " + sweight);                      int cm = 80;                   double cmPer = 0.7;                   RadioButton rbFemale = (RadioButton) findViewById(R.id.rbFemale);                   if (rbFemale.isChecked()) {                       cm = 70;                       cmPer = 0.6;                   }                      int height = Integer.parseInt(sheight);                   double weight = Double.parseDouble(sweight);                      // 计算标准体重                   double standWeight = (height - cm) * cmPer;                   double lowWeight = standWeight - standWeight * 0.1;                   double hightWeight = standWeight + standWeight * 0.1;                      TextView tvScope = (TextView) findViewById(R.id.tvScope);                   String tvtext = "标准体重:" + String.valueOf(standWeight) + "\n体重的合理范围:" + String.valueOf(lowWeight) + "~"                          + String.valueOf(hightWeight);                      // 弹出体重的提示信息                   String text = "";                   int color = 0;                   if (weight >= lowWeight && weight <= hightWeight) {                       text = "亲,是标准体重.继续保持哦...";                       color = Color.GREEN;                       showMessage(text);                   } else if (weight >= (standWeight + standWeight * 0.11)                           && weight <= (standWeight + standWeight * 0.2)) {                       text = "亲,体重过重...";                       color = Color.YELLOW;                       showMessage(text);                   } else if (weight <= (standWeight - standWeight * 0.11)                           && weight >= (standWeight - standWeight * 0.20)) {                       text = "亲,体重过轻...";                       color = Color.YELLOW;                       showMessage(text);                   } else if (weight > (standWeight + standWeight * 0.2)) {                       text = "亲,肥胖...要减肥啦..";                       color = Color.RED;                       showMessage(text);                   } else if (weight < (standWeight - standWeight * 0.2)) {                       text = "亲,太瘦...要多吃啦..";                       color = Color.RED;                       showMessage(text);                   }                      tvScope.setVisibility(View.VISIBLE);                   tvScope.setText(tvtext + "\n" + text);                   tvScope.setTextColor(color);                   break;               case R.id.btnAbout:                   TextView tvAboutContent = (TextView) findViewById(R.id.tvAboutContent);                   if (tvAboutContent.getVisibility() == View.VISIBLE) {                       // 设置控件隐藏                       tvAboutContent.setVisibility(View.GONE);                   } else {                       // 设置控件可见                       tvAboutContent.setVisibility(View.VISIBLE);                   }                   break;           }       }          /**       * 获得文本框的值       *       * @param id       * @return       */       private String getEditText(int id) {           return ((EditText) findViewById(id)).getText().toString();       }          /**       * 显示信息       *       * @param message       */       private void showMessage(String message) {           Toast.makeText(this, message, Toast.LENGTH_SHORT).show();       }          @Override       public boolean onCreateOptionsMenu(Menu menu) {           // Inflate the menu; this adds items to the action bar if it is present.           getMenuInflater().inflate(R.menu.menu_main, menu);           return true;       }          @Override       public boolean onOptionsItemSelected(MenuItem item) {           // Handle action bar item clicks here. The action bar will           // automatically handle clicks on the Home/Up button, so long           // as you specify a parent activity in AndroidManifest.xml.           int id = item.getItemId();              //noinspection SimplifiableIfStatement           if (id == R.id.action_settings) {               return true;           }              return super.onOptionsItemSelected(item);       }   }

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