我有这个应用程序显示一个电阻器（复合图像），下面是四个数字选择器，供用户选择值...一切正常，直到方向改变，并且用户界面不重新创建，我希望保留数字选择器和图像视图的所有显示值...我的保存方法出错了什么？
这是我的主要活动课程
public class MainActivity extends Activity {
RelativeLayout rl;
TextView resistorValue;
MyImageView bandOne, bandTwo, bandThree, tolerance;
int figureOne;
int figureTwo;
int multiplier;
String toleranceRate;
String resistanceDisplayed;
MyNumberPicker pickerOne;
MyNumberPicker pickerTwo;
MyNumberPicker pickerThree;
MyNumberPicker pickerTolerance;
SharedPreferences prefs;
SharedPreferences.Editor editor;
String colorSelected;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//gets shared preferences
prefs = getSharedPreferences("myPrefs", MODE_PRIVATE);
editor = prefs.edit();
//initialize the user interface objects
rl = (RelativeLayout)findViewById(R.id.main_layout);
bandOne = (MyImageView)findViewById(R.id.colorOne);
bandTwo = (MyImageView)findViewById(R.id.colorTwo);
bandThree = (MyImageView)findViewById(R.id.colorThree);
tolerance = (MyImageView)findViewById(R.id.Tolerance);
resistorValue = (TextView)findViewById(R.id.resValue);
pickerOne = (MyNumberPicker)findViewById(R.id.bandOne);
pickerTwo = (MyNumberPicker)findViewById(R.id.bandTwo);
pickerThree = (MyNumberPicker)findViewById(R.id.bandThree);
pickerTolerance = (MyNumberPicker)findViewById(R.id.bandTolerance);
//checks for shared preferences
colorSelected = prefs.getString("background_color", "WHITE");
if(colorSelected.equals("RED")){
rl.setBackgroundColor(Color.RED);
}else if(colorSelected.equals("GREEN")){
rl.setBackgroundColor(Color.GREEN);
}else if(colorSelected.equals("BLUE")){
rl.setBackgroundColor(Color.BLUE);
}else if(colorSelected.equals("BLACK")){
rl.setBackgroundColor(Color.BLACK);
}else{
rl.setBackgroundColor(Color.WHITE);
}
if(savedInstanceState != null){
bandOne = (MyImageView)savedInstanceState.getSerializable("bandOne");
bandTwo = (MyImageView)savedInstanceState.getSerializable("bandTwo");
bandThree = (MyImageView)savedInstanceState.getSerializable("bandThree");
tolerance = (MyImageView)savedInstanceState.getSerializable("tolerance");
pickerOne = (MyNumberPicker)savedInstanceState.getSerializable("pickerOne");
pickerTwo = (MyNumberPicker)savedInstanceState.getSerializable("pickerTwo");
pickerThree = (MyNumberPicker)savedInstanceState.getSerializable("pickerThree");
}
pickerOne.setMinValue(0);
pickerOne.setMaxValue(9);
pickerTwo.setMinValue(0);
pickerTwo.setMaxValue(9);
pickerThree.setMinValue(0);
pickerThree.setMaxValue(9);
pickerTolerance.setMinValue(0);
pickerTolerance.setMaxValue(3);
//sets the displayed values of the number pickers
pickerOne.setDisplayedValues(new String[] { "Black", "Brown", "Red",
"Orange", "Yellow", "Green", "Blue", "Violet", "Grey",
"White" });
pickerTwo.setDisplayedValues(new String[] { "Black", "Brown", "Red",
"Orange", "Yellow", "Green", "Blue", "Violet", "Grey",
"White" });
pickerThree.setDisplayedValues(new String[] { "Black", "Brown", "Red",
"Orange", "Yellow", "Green", "Blue", "Violet", "Grey",
"White" });
pickerTolerance.setDisplayedValues(new String[] { "Brown", "Red", "Gold", "Silver"});
//triggered when numberPickers value are changed
pickerOne.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
@Override
public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
switch (newVal) {
case 0:
bandOne.setImageResource(R.drawable.black);
bandOne.setTag(Integer.valueOf(R.drawable.black));
figureOne = 0;
break;
case 1:
bandOne.setImageResource(R.drawable.brown);
bandOne.setTag(Integer.valueOf(R.drawable.brown));
figureOne = 1;
break;
case 2:
bandOne.setImageResource(R.drawable.red);
figureOne = 2;
break;
case 3:
bandOne.setImageResource(R.drawable.orange);
figureOne = 3;
break;
case 4:
bandOne.setImageResource(R.drawable.yellow);
figureOne = 4;
break;
case 5:
bandOne.setImageResource(R.drawable.green);
figureOne = 5;
break;
case 6:
bandOne.setImageResource(R.drawable.blue);
figureOne = 6;
break;
case 7:
bandOne.setImageResource(R.drawable.violet);
figureOne = 7;
break;
case 8:
bandOne.setImageResource(R.drawable.grey);
figureOne = 8;
break;
case 9:
bandOne.setImageResource(R.drawable.white);
figureOne = 9;
break;
}
calculateResistorValue();
}
});
pickerTwo.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
@Override
public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
switch (newVal) {
case 0:
bandTwo.setImageResource(R.drawable.black);
figureTwo = 0;
break;
case 1:
bandTwo.setImageResource(R.drawable.brown);
figureTwo = 1;
break;
case 2:
bandTwo.setImageResource(R.drawable.red);
figureTwo = 2;
break;
case 3:
bandTwo.setImageResource(R.drawable.orange);
figureTwo = 3;
break;
case 4:
bandTwo.setImageResource(R.drawable.yellow);
figureTwo = 4;
break;
case 5:
bandTwo.setImageResource(R.drawable.green);
figureTwo = 5;
break;
case 6:
bandTwo.setImageResource(R.drawable.blue);
figureTwo = 6;
break;
case 7:
bandTwo.setImageResource(R.drawable.violet);
figureTwo = 7;
break;
case 8:
bandTwo.setImageResource(R.drawable.grey);
figureTwo = 8;
break;
case 9:
bandTwo.setImageResource(R.drawable.white);
figureTwo = 9;
break;
}
calculateResistorValue();
}
});
pickerThree.setOnValueChangedListener(new NumberPicker.OnValueChangeListener() {
@Override
public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
switch (newVal) {
case 0:
bandThree.setImageResource(R.drawable.black);
multiplier = 0;
break;
case 1:
bandThree.setImageResource(R.drawable.brown);
multiplier = 1;
break;
case 2:
bandThree.setImageResource(R.drawable.red);
multiplier = 2;
break;
case 3:
bandThree.setImageResource(R.drawable.orange);
multiplier = 3;
break;
case 4:
bandThree.setImageResource(R.drawable.yellow);
multiplier = 4;
break;
case 5:
bandThree.setImageResource(R.drawable.green);
multiplier = 5;
break;
case 6:
bandThree.setImageResource(R.drawable.blue);
multiplier = 6;
break;
case 7:
bandThree.setImageResource(R.drawable.violet);
multiplier = 7;
break;
case 8:
bandThree.setImageResource(R.drawable.grey);
multiplier = 8;
break;
case 9:
bandThree.setImageResource(R.drawable.white);
multiplier = 9;
break;
}
calculateResistorValue();
}
});
pickerTolerance.setOnValueChangedListener(new NumberPicker.OnValueChangeListener(){
@Override
public void onValueChange(NumberPicker picker, int oldVal, int newVal){
switch(newVal){
case 0:
tolerance.setImageResource(R.drawable.brown);
toleranceRate = "1%";
break;
case 1:
tolerance.setImageResource(R.drawable.red);
toleranceRate = "2%";
break;
case 2:
tolerance.setImageResource(R.drawable.gold);
toleranceRate = "5%";
break;
case 3:
tolerance.setImageResource(R.drawable.silver);
toleranceRate = "10%";
break;
}
calculateResistorValue();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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();
if (id == R.id.preferences_background_color) {
CharSequence colors[] = new CharSequence[] {"red","green", "blue", "black"};
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Pick a color");
builder.setItems(colors, new DialogInterface.OnClickListener() {
//opens a dialog that let the user choose the background color and saves it to shared preferences
@Override
public void onClick(DialogInterface dialog, int which) {
switch(which){
case 0:
rl.setBackgroundColor(Color.RED);
colorSelected="RED";
editor.putString("background_color", colorSelected);
editor.commit();
break;
case 1:
rl.setBackgroundColor(Color.GREEN);
colorSelected="GREEN";
editor.putString("background_color", colorSelected);
editor.commit();
break;
case 2:
rl.setBackgroundColor(Color.BLUE);
colorSelected="BLUE";
editor.putString("background_color", colorSelected);
editor.commit();
break;
case 3:
rl.setBackgroundColor(Color.BLACK);
colorSelected="BLACK";
editor.putString("background_color", colorSelected);
editor.commit();
break;
default:
rl.setBackgroundColor(Color.WHITE);
break;
}
}
});
builder.show();
}
return super.onOptionsItemSelected(item);
}
@Override
public void onSaveInstanceState(Bundle outState) {
outState.putSerializable("bandOne", bandOne);
outState.putSerializable("bandTwo", bandTwo);
outState.putSerializable("bandThree", bandThree);
outState.putSerializable("tolerance", tolerance);
outState.putSerializable("pickerOne", pickerOne);
outState.putSerializable("pickerTwo", pickerTwo);
outState.putSerializable("pickerThree", pickerThree);
super.onSaveInstanceState(outState);
}
//calculates the resistor value and sets text of textView
public void calculateResistorValue(){
double resValue = ((10 * figureOne) + figureTwo) * Math.pow(10, multiplier) / 1000;
String resMessage = null;
if(resValue >= (10^6)){
resValue /= (10^6);
resMessage= Integer.toString((int) resValue) + " M Ohms";
}else if(resValue >= (10^3)){
resValue /= (10^3);
resMessage = Integer.toString((int) resValue) + " k Ohms";
}else{
resMessage = Integer.toString((int) resValue) + " Ohms";
}
resistorValue.setText(resMessage + " " + toleranceRate );
}
}
此外，我还有自定义类My Number Picker和My Image View（并且它们可以正常工作）和XML文件，我相信错误是在我的保存方法或On Create方法中，一旦对象被反序列化。
！[电阻图片] http://www.electronics123.com/page/calculate-resistor-values
答案 0 :(得分：0)
您正在尝试将过多数据保存到捆绑包中。只保存您需要的内容，可能将NumberPicker更改的值存储到主活动类的成员中，然后使用这些成员保存数据。您可以将NumberPicker.OnValueChangedListener中的逻辑移动到公共函数，并在方向更改后拥有活动实例时调用此函数onCreate。您只会从包中加载简单的原始值，而不是复杂的视图对象。
编辑哎呀你已经使用了一个成员，只需创建一个函数并从包中保存/加载这些值并调用该函数来恢复数字选择器！
答案 1 :(得分：0)
尝试保存值：
@Override
public void onSaveInstanceState(Bundle outState) {
outState.putInt("figureOne", pickerOne);
outState.putInt("figureTwo", pickerTwo);
outState.putInt("multiplier", multiplier);
outState.putInt("tolerance", pickerTolerance.getValue());
super.onSaveInstanceState(outState);
}
在onCreate（）中，拥有在所有侦听器设置后恢复值的代码。恢复如下值的代码：
if(savedInstanceState != null){
pickerOne.setValue(savedInstanceState.getInt("figureOne"));
pickerTwo.setValue(savedInstanceState.getInt("figureTwo"));
pickerThree.setValue(savedInstanceState.getInt("multiplier");
pickerTolerance.setValue(savedInstanceState.getInt("tolerance"));
}