我知道有人问过类似的问题，但我严重关注这个问题。 当我关闭应用程序时，它会显示“保存数据”，这意味着我正在调用我的on stop方法，但是当我重新打开应用程序时，它没有提到它是“获取数据”意味着我的onStart方法没有被调用。
中间的代码块似乎是最重要的，我只想包含所有内容，这样如果有人再次碰到我的情况，他们就能看到一切。
在这种情况下如何使用sharedpreferences类来保存背景颜色并在重新打开应用程序时调用onStart方法？ 截至目前，它始终采用默认颜色。 感谢您的时间。
EditText ed;
String background_color;
String Color_Value;
String Message;
int datablock =100;
int selectedItem;
int Color_Position;
int change=0;
View root;
View someView;
SharedPreferences prefer;
SharedPreferences.Editor prefer_edit;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_check_box);
ActionBar bar = getActionBar();
bar.setDisplayShowTitleEnabled(false);
bar.setDisplayShowHomeEnabled(false);
//Hides app title and icon
if (Color_Value!= null){
onStart();
}
else {
}
bar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
//Creates a spinner
ed = (EditText)findViewById(R.id.edit);
final String[] dropdown = getResources().getStringArray(R.array.Colors);
ArrayAdapter <String> adapter = new ArrayAdapter<String>(bar.getThemedContext(),
android.R.layout.simple_spinner_item,android.R.id.text1,dropdown);
//sets up the drop down navigation list in the action bar
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
bar.setListNavigationCallbacks(adapter, new OnNavigationListener(){
@Override
public boolean onNavigationItemSelected(int selectedItem, long arg1) {
//Java always starts counting at zero
if (selectedItem == 0){
someView = findViewById(R.id.layout);
root = someView.getRootView();
root.setBackgroundColor((Color.parseColor("#005640")));
Color_Position =Color.parseColor("#005640");
//prefer_edit.putInt("background_color", ((Color.parseColor("#005640"))));
Toast.makeText(getBaseContext(), "Color Changed", Toast.LENGTH_SHORT).show();
Log.i("At", "Position "+selectedItem);
}
else if (selectedItem == 1){
someView = findViewById(R.id.layout);
root = someView.getRootView();
root.setBackgroundColor((Color.parseColor("#045345")));
Color_Position =Color.parseColor("#045345");
//prefer_edit.putInt("background_color", ((Color.parseColor("#045345"))));
Toast.makeText(getBaseContext(), "Color Changed", Toast.LENGTH_SHORT).show();
Log.i("At", "Position "+selectedItem);
}
else if (selectedItem == 2){
someView = findViewById(R.id.layout);
root = someView.getRootView();
Color_Position =Color.parseColor("#384355");
root.setBackgroundColor((Color.parseColor("#384355")));
//prefer_edit.putInt("background_color", ((Color.parseColor("#384355"))));
Toast.makeText(getBaseContext(), "Color Changed", Toast.LENGTH_SHORT).show();
Log.i("At", "Position "+selectedItem);
}
else if (selectedItem == 3){
someView = findViewById(R.id.layout);
root = someView.getRootView();
Color_Position =Color.parseColor("#990088");
root.setBackgroundColor((Color.parseColor("#990088")));
//prefer_edit.putInt("background_color",((Color.parseColor("#990088"))));
Toast.makeText(getBaseContext(), "Color Changed", Toast.LENGTH_SHORT).show();
Log.i("At", "Position "+selectedItem);
}
else if (selectedItem == 4){
someView = findViewById(R.id.layout);
root = someView.getRootView();
Color_Position =Color.parseColor("#026211");
root.setBackgroundColor((Color.parseColor("#026211")));
// prefer_edit.putInt("background_color", (Color.parseColor("#026211")));
Toast.makeText(getBaseContext(), "Color Changed", Toast.LENGTH_SHORT).show();
Log.i("At", "Position "+selectedItem);
}
return true;
}
});
}
public void onStart（）{
super.onStart（）;
Log.i("Getting Data", "Color is equal to "+Color_Position); SharedPreferences prefer = getSharedPreferences(Color_Value,0); prefer.getInt(background_color, 0); } public void onStop(){ super.onStop(); Log.i("Saving Data", "Color is equal to "+Color_Position); SharedPreferences prefer = getSharedPreferences(Color_Value, 0); SharedPreferences.Editor prefer_edit = prefer.edit(); prefer_edit.putInt(background_color, Color_Position); prefer_edit.commit(); }
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.check_box, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case
R.id.action_settings:
//Pass data between activities here
break;
case
R.id.action_save:
SaveData();
break;
case
R.id.action_error:
LoadData();
break;
case
R.id.action_edit:
ChangeTextColor(change);
change++;
break;
}
return true;
}
public void SaveData(){
Message =ed.getText().toString();
try {
FileOutputStream out = openFileOutput("text.txt", MODE_PRIVATE);
OutputStreamWriter output = new OutputStreamWriter(out);
try{
output.write(Message);
output.flush();
output.close();
Toast.makeText(getBaseContext(), "Save successful", Toast.LENGTH_SHORT).show();
}
catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void LoadData(){
try {
FileInputStream fis = openFileInput("text.txt");
InputStreamReader ins = new InputStreamReader(fis);
//Deserialize the file
char[] Data = new char [datablock];
String final_data ="";
int size;
try {
while((size = ins.read(Data))>0){
String read_data = String.copyValueOf(Data, 0 ,size);
final_data+=read_data;
Data = new char[datablock];
}
Toast.makeText(getBaseContext(), "Message : " + final_data, Toast.LENGTH_SHORT).show();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//Methods galore!
public void ChangeTextColor(int change){
if ((change % 2) == 0) {
// number is even
ed.setHint("enter a message to save");
ed.setTextColor(getResources().getColor(android.R.color.holo_red_dark));
Toast.makeText(getApplicationContext(), "Text color changed to red", Toast.LENGTH_LONG).show();
change++;
}
else {
// number is odd
ed.setHint("enter a message to save");
ed.setTextColor(getResources().getColor(android.R.color.black));
Toast.makeText(getApplicationContext(), "Text color changed to black", Toast.LENGTH_LONG).show();
change++;
}
}
}
答案 0 :(得分：0)
if (Color_Value!= null){
onStart();
}
else {
}
您可以直接在onCreate中检索SharedPreferences的颜色。