1    package com.example.yungchen.ex03; 
2     
3    import android.app.Activity; 
4    import android.support.v7.app.AppCompatActivity; 
5    import android.os.Bundle; 
6    import android.view.MotionEvent; 
7    import android.view.View; 
8    import android.view.ViewGroup; 
9    import android.view.inputmethod.InputMethodManager; 
10   import android.widget.AdapterView; 
11   import android.widget.ArrayAdapter; 
12   import android.widget.Button; 
13   import android.widget.EditText; 
14   import android.widget.Spinner; 
15   import android.widget.TextView; 
16    
17   public class MainActivity extends AppCompatActivity { 
18       protected Spinner spinOP1; 
19       protected TextView tvResult1; 
20       protected Button btnRun1; 
21       protected EditText etVal1, etVal2; 
22       protected int opType = 0; // 0 => +, 1 => -, 2 => *, 3 => / 
23    
24       @Override 
25       protected void onCreate(Bundle savedInstanceState) { 
26           super.onCreate(savedInstanceState); 
27           setContentView(R.layout.activity_main); 
28           setupUI(findViewById(R.id.parent)); 
29    
30           tvResult1 = (TextView) findViewById(R.id.tvResult); 
31    
32           spinOP1 = (Spinner) findViewById(R.id.spinOP); 
33           ArrayAdapter<CharSequence> adapter1 = ArrayAdapter.createFromResource(this, R.array.planets_array, R.layout.support_simple_spinner_dropdown_item); 
34           adapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
35           spinOP1.setAdapter(adapter1); 
36           spinOP1.setOnItemSelectedListener(new SpinnerActivity()); 
37    
38           etVal1 = (EditText) findViewById(R.id.etV1); 
39           etVal2 = (EditText) findViewById(R.id.etV2); 
40    
41           btnRun1 = (Button) findViewById(R.id.runBtn); 
42           btnRun1.setOnClickListener(new View.OnClickListener() { 
43               @Override 
44               public void onClick(View v) { 
45                   float tmpVal = 0.0f, 
46                       v1 = Float.parseFloat(etVal1.getText().toString()), 
47                       v2 = Float.parseFloat(etVal2.getText().toString()); 
48                   switch (opType){ 
49                       case 0: 
50                           tmpVal = v1 + v2; 
51                           break; 
52                       case 1: 
53                           tmpVal = v1 - v2; 
54                           break; 
55                       case 2: 
56                           tmpVal = v1 * v2; 
57                           break; 
58                       case 3: 
59                           tmpVal = v1 / v2; 
60                           break; 
61                   } 
62                   tvResult1.setText(Float.toString(tmpVal)); 
63               } 
64           }); 
65       } 
66    
67       public static void hideSoftKeyboard(Activity activity) { 
68           InputMethodManager inputMethodManager = 
69                   (InputMethodManager)  activity.getSystemService(Activity.INPUT_METHOD_SERVICE); 
70           inputMethodManager.hideSoftInputFromWindow(activity.getCurrentFocus().getWindowToken(), 0); 
71       } 
72    
73       public void setupUI(View view) { 
74           //Set up touch listener for non-text box views to hide keyboard. 
75           if(!(view instanceof EditText)) { 
76               view.setOnTouchListener(new View.OnTouchListener() { 
77                   public boolean onTouch(View v, MotionEvent event) { 
78                       hideSoftKeyboard(MainActivity.this); 
79                       return false; 
80                   } 
81               }); 
82           } 
83    
84           //If a layout container, iterate over children and seed recursion. 
85           if (view instanceof ViewGroup) { 
86               for (int i = 0; i < ((ViewGroup) view).getChildCount(); i++) { 
87                   View innerView = ((ViewGroup) view).getChildAt(i); 
88                   setupUI(innerView); 
89               } 
90           } 
91       } 
92    
93       class SpinnerActivity extends Activity implements AdapterView.OnItemSelectedListener { 
94           public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) { 
95               // An item was selected. You can retrieve the selected item using 
96               // parent.getItemAtPosition(pos) 
97               opType = pos; 
98           } 
99    
100          public void onNothingSelected(AdapterView<?> parent) { 
101              // Another interface callback 
102          } 
103      } 
104  }