android - 每次加载 Activity 时， ListView 都会加倍。

Question

每次加载 Activity 时，listview 都会加倍(每次都会填充以前的数据，使数据出现两次)

public class FragmentActivity extends Activity implements OnItemClickListener{

    private ListView discrepancy_list;
    private DiscrepancyListAdapter list_adapter = null;
    private ArrayList<CommonEntity> discrepancyList = new ArrayList<CommonEntity>();
    private RelativeLayout objRelativeLayout;
    private static int X_CO_ordinate;
    private static int Y_CO_ordinate;
    private ArrayList<String> arrlstCo_ordinate;
    private ArrayList<String> arrlst_Count;
    private boolean touch = true,isOnLaunch = false;
    private int editText_ID=1,count=1;
    private EditText objEditText;
    private SortedMap<Integer,String> mapDefect=null;
    private int final_position; 
    private ImageButton objImageButton;
    private DatabaseHandler db;
    Bitmap StoredBitmap;
    Drawable StoredDrawable;
    private static int dataSet = 0;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState){

         super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mapDefect=new TreeMap<Integer, String>();
        arrlstCo_ordinate=new ArrayList<String>();
        arrlst_Count=new ArrayList<String>();
        discrepancy_list = (ListView)findViewById(R.id.number_list);
        discrepancy_list.setOnItemClickListener(this);
        db = new DatabaseHandler(this);

        objRelativeLayout=(RelativeLayout) findViewById(R.id.RelativeLayout);
        objRelativeLayout.setOnTouchListener(new View.OnTouchListener(){
            public boolean onTouch(View v, MotionEvent event){
                String strEditText;
                if(!checkForDataSaved()){
                if(touch){
                    Log.d("ON", "onTouch called");
                    X_CO_ordinate=(int) event.getX() ; 
                    Y_CO_ordinate=(int) event.getY();

                    boolean isNotDuplicate=checkDuplicateElement(X_CO_ordinate,Y_CO_ordinate);
                    if(isNotDuplicate){
                        Log.d("TOUCH", "TOUCH"+X_CO_ordinate+"|"+Y_CO_ordinate+"|"+"Touch :");
                        if(objEditText != null){
                            strEditText=objEditText.getText().toString();
                            Log.d("Err", "EditText not null"+strEditText);

                            if(strEditText != null && strEditText.length() != 0){
//                              if(chekMapEntry(objEditText.getId(), objEditText.getText().toString(), ""+X_CO_ordinate+"|"+Y_CO_ordinate))
//                              {
                                arrlst_Count.add(""+X_CO_ordinate+"|"+Y_CO_ordinate);
                                arrlstCo_ordinate.add(""+X_CO_ordinate+"|"+Y_CO_ordinate);
                                mapDefect.put(objEditText.getId(),objEditText.getText().toString());
                                Log.d("Err", "In Touch Map Size :"+mapDefect.size() +"Arr List Size :"+arrlstCo_ordinate.size());
                                objEditText.setVisibility(View.INVISIBLE);
                                //}else{Toast.makeText(FragmentActivity.this, "Duplicate map entry", Toast.LENGTH_LONG).show();}
                                addEditText();
                                Log.d("Err", "String not null");
                            }else{
                                Log.d("Err", "String null");
                                Toast.makeText(FragmentActivity.this, "Please log the defect ::: in onTouch()", Toast.LENGTH_LONG).show();
                            }
                        }else{
                            Log.d("Err", "EditText  null");
                            arrlst_Count.add(""+X_CO_ordinate+"|"+Y_CO_ordinate);
                            arrlstCo_ordinate.add(""+X_CO_ordinate+"|"+Y_CO_ordinate);
                            Log.d("Err", "In Touch else Map Size :"+mapDefect.size() +"Arr List Size :"+arrlstCo_ordinate.size());
                            Drawable relative_image_bg = objRelativeLayout.getBackground();
                            Bitmap bitmap = ((BitmapDrawable)relative_image_bg).getBitmap();
                            Bitmap bitmap2 = ((BitmapDrawable)(getResources().getDrawable(R.drawable.no_image_screen_new))).getBitmap();

                            if(bitmap.sameAs(bitmap2)){
                                Toast.makeText(FragmentActivity.this, "Please capture the image", Toast.LENGTH_LONG).show();
                            }else{
                                Toast.makeText(FragmentActivity.this, "Not equal..", Toast.LENGTH_LONG).show();
                                addEditText();
                            }
                        }
                    }
                    touch=false;
                }else{
                    touch=true;
                }
            }
                return true;
            }

            private boolean checkDuplicateElement(int x_CO_ordinate,int y_CO_ordinate){
                String strX=String.valueOf(x_CO_ordinate);
                String strY=String.valueOf(y_CO_ordinate);

                for(int i=0;i<arrlstCo_ordinate.size();i++){
                    String strResult=arrlstCo_ordinate.get(i);
                    String []arrResult=StringUtils.split(strResult, "|");
                    String strTemp_X=arrResult[0];
                    String strTemp_Y=arrResult[1];
                    Log.d("CO", ""+strTemp_X+strTemp_Y+"|"+strX+strY);

                    if(strTemp_X.equalsIgnoreCase(strX) || strTemp_Y.equalsIgnoreCase(strY)){
                        Log.d("DUP", "Duplicate element is not allow");
                        Toast.makeText(FragmentActivity.this, "Duplicate element is not allow", Toast.LENGTH_SHORT).show();
                        return false;
                    }
                }
                return true;
            }
        });

        //add list in main.xml

        addList();
        getDefects();


    }

    private void addList(){


        discrepancyList = LocalDatabaseOperations.callDBToGetList(this);

        list_adapter = new DiscrepancyListAdapter(this, discrepancyList);
        discrepancy_list.setAdapter(list_adapter);
        isOnLaunch = true;
        discrepancy_list.performItemClick(null, 0, discrepancy_list.getFirstVisiblePosition());


    }

    private void getDefects(){

        if(LocalDatabaseOperations.callDBToGetDefects(this) == true){
            fechCoordinate();
            addViewEditText();

        }
    }

因此，这是在 LHS 上加载“差异列表”并在 fragment 的 RHS 上加载列表中第一项信息的 Activity 。但是当我返回并返回到此屏幕时，会加载相同的 Activity 以使其加载 Activity 。这应该发生。但是，之前的数据也存在，使整个数据翻了一番。

Answer 1

在您的 callDBToGetList() 函数中，我假设您正在返回一个列表(比如 myList)。将此行作为 callDBToGetList() 函数的第一行。

myList.clear();

将 myList 替换为您要返回的列表的名称。