Android 开发笔记___Application操作全局变量

只要app在运行中，他就是一个application。因此可以用它来保存一些全局变量

 1 package com.example.alimjan.hello_world;
 2 
 3 import android.app.Application;
 4 
 5 import java.util.HashMap;
 6 
 7 /**
 8  * Created by alimjan on 7/5/2017.
 9  */
10 
11         import android.graphics.Bitmap;
12         import android.util.Log;
13 
14 
15 public class MainApplication extends Application {
16 
17     private final static String TAG = "MainApplication";
18     private static MainApplication mApp;
19     public HashMap<String, String> mInfoMap = new HashMap<String, String>();
20 
21     public static MainApplication getInstance() {
22         return mApp;
23     }
24 
25     @Override
26     public void onCreate() {
27         super.onCreate();
28         mApp = this;
29         Log.d(TAG, "onCreate");
30     }
31 
32     @Override
33     public void onTerminate() {
34         Log.d(TAG, "onTerminate");
35         super.onTerminate();
36     }
37 
38     public HashMap<Long, Bitmap> mIconMap = new HashMap<Long, Bitmap>();
39 
40 
41 
42 }

write

  1 package com.example.alimjan.hello_world;
  2 
  3 /**
  4  * Created by alimjan on 7/5/2017.
  5  */
  6 
  7 
  8         import android.content.Context;
  9         import android.content.Intent;
 10         import android.os.Bundle;
 11         import android.support.v7.app.AppCompatActivity;
 12         import android.view.View;
 13         import android.view.View.OnClickListener;
 14         import android.widget.AdapterView;
 15         import android.widget.ArrayAdapter;
 16         import android.widget.EditText;
 17         import android.widget.Spinner;
 18         import android.widget.Toast;
 19         import android.widget.AdapterView.OnItemSelectedListener;
 20         import com.example.alimjan.hello_world.Utils.DateUtil;
 21 
 22 
 23 public class class_4_4_2 extends AppCompatActivity implements OnClickListener {
 24 
 25     private EditText et_name;
 26     private EditText et_age;
 27     private EditText et_height;
 28     private EditText et_weight;
 29     private boolean bMarried = false;
 30 
 31     @Override
 32     protected void onCreate(Bundle savedInstanceState) {
 33         super.onCreate(savedInstanceState);
 34         setContentView(R.layout.code_4_4_2);
 35         et_name = (EditText) findViewById(R.id.et_name);
 36         et_age = (EditText) findViewById(R.id.et_age);
 37         et_height = (EditText) findViewById(R.id.et_height);
 38         et_weight = (EditText) findViewById(R.id.et_weight);
 39         findViewById(R.id.btn_save).setOnClickListener(this);
 40 
 41         ArrayAdapter<String> typeAdapter = new ArrayAdapter<String>(this,
 42                 R.layout.item_select, typeArray);
 43         typeAdapter.setDropDownViewResource(R.layout.item_dropdown);
 44         Spinner sp_married = (Spinner) findViewById(R.id.sp_married);
 45         sp_married.setPrompt("请选择婚姻状况");
 46         sp_married.setAdapter(typeAdapter);
 47         sp_married.setSelection(0);
 48         sp_married.setOnItemSelectedListener(new TypeSelectedListener());
 49     }
 50 
 51     private String[] typeArray = {"未婚", "已婚"};
 52     class TypeSelectedListener implements OnItemSelectedListener {
 53         public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
 54             bMarried = (arg2==0)?false:true;
 55         }
 56 
 57         public void onNothingSelected(AdapterView<?> arg0) {
 58         }
 59     }
 60 
 61     @Override
 62     public void onClick(View v) {
 63         if (v.getId() == R.id.btn_save) {
 64             String name = et_name.getText().toString();
 65             String age = et_age.getText().toString();
 66             String height = et_height.getText().toString();
 67             String weight = et_weight.getText().toString();
 68             if (name==null || name.length()<=0) {
 69                 showToast("请先填写姓名");
 70                 return;
 71             }
 72             if (age==null || age.length()<=0) {
 73                 showToast("请先填写年龄");
 74                 return;
 75             }
 76             if (height==null || height.length()<=0) {
 77                 showToast("请先填写身高");
 78                 return;
 79             }
 80             if (weight==null || weight.length()<=0) {
 81                 showToast("请先填写体重");
 82                 return;
 83             }
 84 
 85             MainApplication app = MainApplication.getInstance();
 86             app.mInfoMap.put("name", name);
 87             app.mInfoMap.put("age", age);
 88             app.mInfoMap.put("height", height);
 89             app.mInfoMap.put("weight", weight);
 90             app.mInfoMap.put("married", typeArray[bMarried==false?0:1]);
 91             app.mInfoMap.put("update_time", DateUtil.getCurDateStr("yyyy-MM-dd HH:mm:ss"));
 92             showToast("数据已写入全局内存");
 93         }
 94     }
 95 
 96     private void showToast(String desc) {
 97         Toast.makeText(this, desc, Toast.LENGTH_SHORT).show();
 98     }
 99 
100     public static void startHome(Context mcontext){
101         Intent intent = new Intent(mcontext,class_4_4_2.class);
102         mcontext.startActivity(intent);
103     }
104 
105 }
  1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  2     android:layout_width="match_parent"
  3     android:layout_height="match_parent"
  4     android:focusable="true"
  5     android:focusableInTouchMode="true"
  6     android:orientation="vertical"
  7     android:padding="10dp" >
  8 
  9     <RelativeLayout
 10         android:layout_width="match_parent"
 11         android:layout_height="50dp" >
 12 
 13         <TextView
 14             android:id="@+id/tv_name"
 15             android:layout_width="wrap_content"
 16             android:layout_height="match_parent"
 17             android:layout_alignParentLeft="true"
 18             android:gravity="center"
 19             android:text="姓名："
 20             android:textColor="@color/black"
 21             android:textSize="17sp" />
 22 
 23         <EditText
 24             android:id="@+id/et_name"
 25             android:layout_width="match_parent"
 26             android:layout_height="match_parent"
 27             android:layout_marginBottom="5dp"
 28             android:layout_marginTop="5dp"
 29             android:layout_toRightOf="@+id/tv_name"
 30             android:background="@drawable/editext_selector"
 31             android:gravity="left|center"
 32             android:hint="请输入姓名"
 33             android:inputType="text"
 34             android:maxLength="12"
 35             android:textColor="@color/black"
 36             android:textColorHint="@color/grey"
 37             android:textCursorDrawable="@drawable/text_cursor"
 38             android:textSize="17sp" />
 39     </RelativeLayout>
 40 
 41     <RelativeLayout
 42         android:layout_width="match_parent"
 43         android:layout_height="50dp" >
 44 
 45         <TextView
 46             android:id="@+id/tv_age"
 47             android:layout_width="wrap_content"
 48             android:layout_height="match_parent"
 49             android:layout_alignParentLeft="true"
 50             android:gravity="center"
 51             android:text="年龄："
 52             android:textColor="@color/black"
 53             android:textSize="17sp" />
 54 
 55         <EditText
 56             android:id="@+id/et_age"
 57             android:layout_width="match_parent"
 58             android:layout_height="match_parent"
 59             android:layout_marginBottom="5dp"
 60             android:layout_marginTop="5dp"
 61             android:layout_toRightOf="@+id/tv_age"
 62             android:background="@drawable/editext_selector"
 63             android:gravity="left|center"
 64             android:hint="请输入年龄"
 65             android:inputType="number"
 66             android:maxLength="2"
 67             android:textColor="@color/black"
 68             android:textColorHint="@color/grey"
 69             android:textCursorDrawable="@drawable/text_cursor"
 70             android:textSize="17sp" />
 71     </RelativeLayout>
 72 
 73     <RelativeLayout
 74         android:layout_width="match_parent"
 75         android:layout_height="50dp" >
 76 
 77         <TextView
 78             android:id="@+id/tv_height"
 79             android:layout_width="wrap_content"
 80             android:layout_height="match_parent"
 81             android:layout_alignParentLeft="true"
 82             android:gravity="center"
 83             android:text="身高："
 84             android:textColor="@color/black"
 85             android:textSize="17sp" />
 86 
 87         <EditText
 88             android:id="@+id/et_height"
 89             android:layout_width="match_parent"
 90             android:layout_height="match_parent"
 91             android:layout_marginBottom="5dp"
 92             android:layout_marginTop="5dp"
 93             android:layout_toRightOf="@+id/tv_height"
 94             android:background="@drawable/editext_selector"
 95             android:gravity="left|center"
 96             android:hint="请输入身高"
 97             android:inputType="number"
 98             android:maxLength="3"
 99             android:textColor="@color/black"
100             android:textColorHint="@color/grey"
101             android:textCursorDrawable="@drawable/text_cursor"
102             android:textSize="17sp" />
103     </RelativeLayout>
104 
105     <RelativeLayout
106         android:layout_width="match_parent"
107         android:layout_height="50dp" >
108 
109         <TextView
110             android:id="@+id/tv_weight"
111             android:layout_width="wrap_content"
112             android:layout_height="match_parent"
113             android:layout_alignParentLeft="true"
114             android:gravity="center"
115             android:text="体重："
116             android:textColor="@color/black"
117             android:textSize="17sp" />
118 
119         <EditText
120             android:id="@+id/et_weight"
121             android:layout_width="match_parent"
122             android:layout_height="match_parent"
123             android:layout_marginBottom="5dp"
124             android:layout_marginTop="5dp"
125             android:layout_toRightOf="@+id/tv_weight"
126             android:background="@drawable/editext_selector"
127             android:gravity="left|center"
128             android:hint="请输入体重"
129             android:inputType="numberDecimal"
130             android:maxLength="5"
131             android:textColor="@color/black"
132             android:textColorHint="@color/grey"
133             android:textCursorDrawable="@drawable/text_cursor"
134             android:textSize="17sp" />
135     </RelativeLayout>
136 
137     <RelativeLayout
138         android:layout_width="match_parent"
139         android:layout_height="50dp" >
140 
141         <TextView
142             android:id="@+id/tv_married"
143             android:layout_width="wrap_content"
144             android:layout_height="match_parent"
145             android:layout_alignParentLeft="true"
146             android:gravity="center"
147             android:text="婚否："
148             android:textColor="@color/black"
149             android:textSize="17sp" />
150 
151         <Spinner
152             android:id="@+id/sp_married"
153             android:layout_width="match_parent"
154             android:layout_height="match_parent"
155             android:layout_toRightOf="@+id/tv_married"
156             android:gravity="left|center"
157             android:spinnerMode="dialog" />
158     </RelativeLayout>
159 
160     <Button
161         android:id="@+id/btn_save"
162         android:layout_width="match_parent"
163         android:layout_height="wrap_content"
164         android:text="保存到全局内存"
165         android:textColor="@color/black"
166         android:textSize="20sp" />
167 
168 </LinearLayout>

read

 1 package com.example.alimjan.hello_world;
 2 
 3 import java.util.Map;
 4 
 5 /**
 6  * Created by alimjan on 7/5/2017.
 7  */
 8 
 9 
10 import android.content.Context;
11 import android.content.Intent;
12 import android.os.Bundle;
13         import android.support.v7.app.AppCompatActivity;
14         import android.widget.TextView;
15 
16 
17 public class class_4_4_2_1 extends AppCompatActivity {
18 
19     private TextView tv_app;
20 
21     @Override
22     protected void onCreate(Bundle savedInstanceState) {
23         super.onCreate(savedInstanceState);
24         setContentView(R.layout.code_4_4_2_1);
25         tv_app = (TextView) findViewById(R.id.tv_app);
26         readAppMemory();
27     }
28 
29     private void readAppMemory() {
30         String desc = "全局内存中保存的信息如下：";
31         MainApplication app = MainApplication.getInstance();
32         Map<String, String> mapParam = app.mInfoMap;
33         for (Map.Entry<String, String> item_map : mapParam.entrySet()) {
34             desc = String.format("%s\n　%s的取值为%s",
35                     desc, item_map.getKey(), item_map.getValue());
36         }
37         if (mapParam==null || mapParam.size()<=0) {
38             desc = "全局内存中保存的信息为空";
39         }
40         tv_app.setText(desc);
41     }
42 
43     public static void startHome(Context mcontext){
44         Intent intent = new Intent(mcontext,class_4_4_2_1.class);
45         mcontext.startActivity(intent);
46     }
47 
48 }
 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     android:layout_width="match_parent"
 3     android:layout_height="match_parent"
 4     android:focusable="true"
 5     android:focusableInTouchMode="true"
 6     android:orientation="vertical"
 7     android:padding="10dp" >
 8 
 9     <TextView
10         android:id="@+id/tv_app"
11         android:layout_width="match_parent"
12         android:layout_height="wrap_content"
13         android:textColor="@color/black"
14         android:textSize="17sp" />
15 
16 </LinearLayout>

 

posted @ 2017-07-05 18:27  alm  阅读(1602)  评论(0)  编辑  收藏  举报