活动重新启动时如何保存编辑文本字段答案

【问题标题】：How to save edit text field when activity restarts活动重新启动时如何保存编辑文本字段
【发布时间】：2016-12-29 12:38:47
【问题描述】：

尝试创建我的应用程序的一部分但遇到了困难。当您从列表中添加一个下拉列表时，您会转到一个新活动以添加另一个。然后，当您返回活动时，先前的下拉选择就消失了。

有没有办法保存第一个下拉选择，以便当您返回活动时它仍然存在？

下面是我从下拉列表中添加选项的代码。

public String s;

TextView myLocationText;
TextView myLocationText2;
TextView myLocationText3;
TextView myLocationText4;
TextView myLocationText5;

EditText textCheck;
EditText textCheck2;
EditText textCheck3;
EditText textCheck4;
EditText textCheck5;

static int i = 1;

TextView testView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.view_activity_second);

    s = getIntent().getStringExtra("SELECTED_ACTIVITY");

    //Display selected activity in log
    Log.d("SecondActivity::" + s, "Extra");

    textCheck = (EditText) this.findViewById(R.id.sampleTextData);
    textCheck2 = (EditText) this.findViewById(R.id.sampleTextData2);
    textCheck3 = (EditText) this.findViewById(R.id.sampleTextData3);
    textCheck4 = (EditText) this.findViewById(R.id.sampleTextData4);
    textCheck5 = (EditText) this.findViewById(R.id.sampleTextData5);

    //Display selected activity
    if ((textCheck.getText().toString().equals("")) && i == 1) {
        myLocationText = (TextView) findViewById(R.id.sampleTextData);
        myLocationText.setText(s);
        i++;
    } else if ((textCheck2.getText().toString().equals("")) && i == 2) {
        myLocationText2 = (TextView) findViewById(R.id.sampleTextData2);
        myLocationText2.setText(s);
        i++;
    } else if ((textCheck3.getText().toString().equals("")) && i == 3) {
        myLocationText3 = (TextView) findViewById(R.id.sampleTextData3);
        myLocationText3.setText(s);
        i++;
    } else if ((textCheck4.getText().toString().equals("")) && i == 4) {
        myLocationText4 = (TextView) findViewById(R.id.sampleTextData4);
        myLocationText4.setText(s);
        i++;
    } else if ((textCheck5.getText().toString().equals("")) && i == 5) {
        myLocationText5 = (TextView) findViewById(R.id.sampleTextData5);
        myLocationText5.setText(s);
        i++;
    }

我已经从上面的代码中编辑了我的代码，它更简洁，并且我已经包含了我认为需要但仍然没有很多运气的保存功能。见下文。

public String s;

EditText textCheck;
EditText textCheck2;
EditText textCheck3;
EditText textCheck4;
EditText textCheck5;

static int i = 1;

TextView testView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.view_activity_second);
    s = getIntent().getStringExtra("SELECTED_ACTIVITY");

    //Display selected activity in log
    Log.d("SecondActivity::" + s, "Extra");

    //Look for saved text from activity
    textCheck = (EditText) this.findViewById(R.id.sampleTextData);
    if(savedInstanceState != null) {
        String editTextString = savedInstanceState.getString("textCheck");
        textCheck.setText(editTextString);
    }
    textCheck2 = (EditText) this.findViewById(R.id.sampleTextData2);
    if(savedInstanceState != null) {
        String editTextString2 = savedInstanceState.getString("textCheck2");
        textCheck2.setText(editTextString2);
    }
    textCheck3 = (EditText) this.findViewById(R.id.sampleTextData3);
    if(savedInstanceState != null) {
        String editTextString3 = savedInstanceState.getString("textCheck3");
        textCheck3.setText(editTextString3);
    }
    textCheck4 = (EditText) this.findViewById(R.id.sampleTextData4);
    if(savedInstanceState != null) {
        String editTextString4 = savedInstanceState.getString("textCheck4");
        textCheck4.setText(editTextString4);
    }
    textCheck5 = (EditText) this.findViewById(R.id.sampleTextData5);
    if(savedInstanceState != null) {
        String editTextString5 = savedInstanceState.getString("textCheck5");
        textCheck5.setText(editTextString5);
    }

    //Display selected activity
    if ((textCheck.getText().toString().equals("")) && i == 1) {
        textCheck.setText(s);
        i++;
    } else if ((textCheck2.getText().toString().equals("")) && i == 2) {
        textCheck2.setText(s);
        i++;
    } else if ((textCheck3.getText().toString().equals("")) && i == 3) {
        textCheck3.setText(s);
        i++;
    } else if ((textCheck4.getText().toString().equals("")) && i == 4) {
        textCheck4.setText(s);
        i++;
    } else if ((textCheck5.getText().toString().equals("")) && i == 5) {
        textCheck5.setText(s);
        i++;
    } else if (i == 6){
        return;
    }
}

//Save text within activity
@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putString("textCheck", textCheck.getText().toString());
    outState.putString("textCheck2", textCheck2.getText().toString());
    outState.putString("textCheck3", textCheck3.getText().toString());
    outState.putString("textCheck4", textCheck4.getText().toString());
    outState.putString("textCheck5", textCheck5.getText().toString());
}

//Retrieve previous activity text
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    if (savedInstanceState!=null) {
        textCheck.setText(savedInstanceState.getString("textCheck"));
        textCheck2.setText(savedInstanceState.getString("textCheck2"));
        textCheck3.setText(savedInstanceState.getString("textCheck3"));
        textCheck4.setText(savedInstanceState.getString("textCheck4"));
        textCheck5.setText(savedInstanceState.getString("textCheck5"));
    }
}

【问题讨论】：

使用 onSaveInstanceState(bundle) 并在 onCreate(bundle) 包中取回它。
此代码将帮助您：android-er.blogspot.in/2011/09/onsaveinstancestate-and.html
When to use saveInstanceState() method?的可能重复

标签： java android android-studio

【解决方案1】：

覆盖活动中的OnSaveInstanceState()，并使用唯一键将所有需要的值放入包中。喜欢：

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putString("EDITTEXT", mEditText.getText().toString());
}

使用相同的键检索onCreate(Bundle savedInstanceState) 中的值。喜欢：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.view_activity_second);
    textCheck = (EditText) this.findViewById(R.id.sampleTextData);
    //this will be false for first time but will be true when activity recreates.
    if(savedInstanceState != null) {
        String editTextString = savedInstanceState.getString("EDITTEXT");
        textCheck.setText(editTextString);
    }
}

【讨论】：

感谢您，我已经创建了 onSaveInstanceState 方法并在我的 onCreate 方法中添加了代码，但是当我返回活动时，下拉菜单中添加的文本似乎仍然消失了。跨度>

【解决方案2】：

将 EditText 的内容保存在共享首选项中

SharedPreferences.Editor editor = getSharedPreferences(preferences1,
MODE_PRIVATE).edit();
editor.putString("text", "editTextsString");
editor.commit();

然后在活动创建或恢复时，调用共享首选项：

 SharedPreferences prefs = getSharedPreferences(preferences1, MODE_PRIVATE); 
 String Text = prefs.getString("text", null);

并将编辑文本设置为字符串变量：Text

【讨论】：

当你有onSaveInstanceState() 为什么要进行像sharedPreference 这样昂贵的操作。
这是我能想到的解决 op 问题的唯一方法——它可能不是最顺利的，但我认为它可以满足 op 的要求。

【解决方案3】：

 public String s;

TextView myLocationText;
TextView myLocationText2;
TextView myLocationText3;
TextView myLocationText4;
TextView myLocationText5;

EditText textCheck;
EditText textCheck2;
EditText textCheck3;
EditText textCheck4;
EditText textCheck5;

static int i = 1;

TextView testView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.view_activity_second);

    s = getIntent().getStringExtra("SELECTED_ACTIVITY");

    //Display selected activity in log
    Log.d("SecondActivity::" + s, "Extra");

    textCheck = (EditText) this.findViewById(R.id.sampleTextData);
    textCheck2 = (EditText) this.findViewById(R.id.sampleTextData2);
    textCheck3 = (EditText) this.findViewById(R.id.sampleTextData3);
    textCheck4 = (EditText) this.findViewById(R.id.sampleTextData4);
    textCheck5 = (EditText) this.findViewById(R.id.sampleTextData5);

    //Display selected activity
    if ((textCheck.getText().toString().equals("")) && i == 1) {
        myLocationText = (TextView) findViewById(R.id.sampleTextData);
        myLocationText.setText(s);
        i++;
    } else if ((textCheck2.getText().toString().equals("")) && i == 2) {
        myLocationText2 = (TextView) findViewById(R.id.sampleTextData2);
        myLocationText2.setText(s);
        i++;
    } else if ((textCheck3.getText().toString().equals("")) && i == 3) {
        myLocationText3 = (TextView) findViewById(R.id.sampleTextData3);
        myLocationText3.setText(s);
        i++;
    } else if ((textCheck4.getText().toString().equals("")) && i == 4) {
        myLocationText4 = (TextView) findViewById(R.id.sampleTextData4);
        myLocationText4.setText(s);
        i++;
    } else if ((textCheck5.getText().toString().equals("")) && i == 5) {
        myLocationText5 = (TextView) findViewById(R.id.sampleTextData5);
        myLocationText5.setText(s);
        i++;
    }


}

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putString("textCheck", textCheck.getText().toString());
    outState.putString("textCheck2", textCheck2.getText().toString());
    outState.putString("textCheck3", textCheck3.getText().toString());
    outState.putString("textCheck4", textCheck4.getText().toString());
    outState.putString("textCheck5", textCheck5.getText().toString());
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    if (savedInstanceState!=null) {
        textCheck.setText(savedInstanceState.getString("textCheck"));
        textCheck2.setText(savedInstanceState.getString("textCheck2"));
        textCheck3.setText(savedInstanceState.getString("textCheck3"));
        textCheck4.setText(savedInstanceState.getString("textCheck4"));
        textCheck5.setText(savedInstanceState.getString("textCheck5"));
    }
}

只需复制并粘贴此代码即可。希望它会起作用。

【讨论】：

不幸的是没有，添加了两个底部方法但仍然没有保存。
没有错误，该应用程序仍然可以正常工作。由于 i++，它会将其他活动添加到下面的字段中，但是上面的字段在返回活动时似乎仍然是空白的。

【解决方案4】：

Use OnSaveInstanceState() to save the value during restart of an activity .

use below code : 

@Override
protected void onSaveInstanceState(Bundle bundle) {
    super.onSaveInstanceState(bundle);
    bundle.putString("Key","Edit Text value");
}

and get the data using  below code :


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity);
    if(savedInstanceState != null) {
        String value = savedInstanceState.getString("Key");
    }
}

【讨论】：