试图获取Android Studio sharedPreference以使其正常工作

问题描述 投票：0回答：1

这是一小段代码，但是我已经对其进行了很多次调整，我不知道它是否仍然明智。我正在尝试将String保存到持久的sharePreference存储中，并在应用启动时获取该字符串。

由于不保存字符串，因此每次尝试输入字符串时代码都会崩溃。'''公共类MainActivity扩展了AppCompatActivity {

TextView displayHours;
EditText userYears;
EditText userAge;
TextView outputText;
SharedPreferences sharedPref;

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

    displayHours = (TextView) findViewById(R.id.displayHours);
    userYears = (EditText) findViewById(R.id.userYears);
    userAge = (EditText) findViewById(R.id.userAge);
    outputText = (TextView) findViewById(R.id.outputText);

    sharedPref = getPreferences(Context.MODE_PRIVATE);
    String defaultValue = getString(R.string.user_age);
    String savedAge = sharedPref.getString("AgeData", defaultValue);
    setAgeIfEmpty(savedAge);

    Button calcButton = (Button) findViewById(R.id.calcButton);
    calcButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            float range = 300;

            if (Float.parseFloat(userYears.getText().toString()) <= range) {
                float years = Float.parseFloat(userYears.getText().toString());
                float totalHours = years*365*24;
                String setHours = Float.toString(totalHours);
                displayHours.setText(setHours);
            }
        }
    });

    EditText ageText = (EditText) findViewById(R.id.userAge);
    ageText.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            String ageNumber = userAge.getText().toString();
            userAge.setText(ageNumber);

            sharedPref = getPreferences(Context.MODE_PRIVATE);
            SharedPreferences.Editor editor = sharedPref.edit();
            editor.putString("AgeData", ageNumber);
            editor.apply();

            Toast myToast = Toast.makeText(getApplicationContext(), "Age Saved!",
                    Toast.LENGTH_SHORT);
            myToast.show();
        }
    });

    ageText.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        @SuppressLint("StringFormatMatches")
        @Override
        public void afterTextChanged(Editable s) {
            int age = Integer.parseInt(userAge.getText().toString());
            int intYears = Integer.parseInt(userYears.getText().toString());
            String text;

            if (age < intYears/3){
                text = getString(R.string.Message_1, age);
                outputText.setText(text);
            }

            else if (intYears < 8 || Integer.parseInt(displayHours.getText().toString()) < 40000){
                text = getString(R.string.Message_3, displayHours.getText().toString());
                outputText.setText(text);
            }

            else{
                text = getString(R.string.Message_2, age);
                outputText.setText(text);
            }
        }
    });
}

public void setAgeIfEmpty(String data) {
    if (!TextUtils.isEmpty(userAge.getText())) {
        userAge.setText(data);
    }
}

回溯；

I/zygote:     at void com.android.internal.os.Zygote$MethodAndArgsCaller.run() (Zygote.java:240)
    at void com.android.internal.os.ZygoteInit.main(java.lang.String[]) (ZygoteInit.java:767)
D/OpenGLRenderer: HWUI GL Pipeline
D/: HostConnection::get() New Host Connection established 0xa4ffbf40, tid 7284
I/OpenGLRenderer: Initialized EGL, version 1.4
D/OpenGLRenderer: Swap behavior 1
W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
D/OpenGLRenderer: Swap behavior 0
D/EGL_emulation: eglCreateContext: 0x994f6be0: maj 3 min 1 rcv 4
D/EGL_emulation: eglMakeCurrent: 0x994f6be0: ver 3 1 (tinfo 0x98f23590)
E/eglCodecCommon: glUtilsParamSize: unknow param 0x000082da
    glUtilsParamSize: unknow param 0x000082da
I/Choreographer: Skipped 36 frames!  The application may be doing too much work on its main thread.
D/EGL_emulation: eglMakeCurrent: 0x994f6be0: ver 3 1 (tinfo 0x98f23590)
W/View: dispatchProvideAutofillStructure(): not laid out, ignoring
I/AssistStructure: Flattened final assist data: 3872 bytes, containing 1 windows, 14 views
I/zygote: Background concurrent copying GC freed 3588(934KB) AllocSpace objects, 2(40KB) LOS objects, 67% free, 756KB/2MB, paused 4.816ms total 110.298ms
I/zygote: Do partial code cache collection, code=20KB, data=29KB
I/zygote: After code cache collection, code=20KB, data=29KB
    Increasing code cache capacity to 128KB
I/zygote: Do partial code cache collection, code=49KB, data=51KB
    After code cache collection, code=49KB, data=51KB
    Increasing code cache capacity to 256KB
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.lifewirehours, PID: 7243
    java.lang.NumberFormatException: For input string: ""
        at java.lang.Integer.parseInt(Integer.java:620)
        at java.lang.Integer.parseInt(Integer.java:643)
        at com.example.lifewirehours.MainActivity$3.afterTextChanged(MainActivity.java:98)
        at android.widget.TextView.sendAfterTextChanged(TextView.java:9375)
        at android.widget.TextView$ChangeWatcher.afterTextChanged(TextView.java:11917)
        at android.text.SpannableStringBuilder.sendAfterTextChanged(SpannableStringBuilder.java:1262)
        at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:574)
        at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:504)
        at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:502)
        at android.text.method.NumberKeyListener.onKeyDown(NumberKeyListener.java:131)
        at android.widget.TextView.doKeyDown(TextView.java:7316)
        at android.widget.TextView.onKeyDown(TextView.java:7093)
        at android.view.KeyEvent.dispatch(KeyEvent.java:2691)
        at android.view.View.dispatchKeyEvent(View.java:11662)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)
        at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)
        at com.android.internal.policy.DecorView.superDispatchKeyEvent(DecorView.java:437)
        at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1818)
        at androidx.core.view.KeyEventDispatcher.activitySuperDispatchKeyEventPre28(KeyEventDispatcher.java:130)
        at androidx.core.view.KeyEventDispatcher.dispatchKeyEvent(KeyEventDispatcher.java:87)
        at androidx.core.app.ComponentActivity.dispatchKeyEvent(ComponentActivity.java:133)
        at androidx.appcompat.app.AppCompatActivity.dispatchKeyEvent(AppCompatActivity.java:558)
        at androidx.appcompat.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:59)
        at androidx.appcompat.app.AppCompatDelegateImpl$AppCompatWindowCallback.dispatchKeyEvent(AppCompatDelegateImpl.java:2814)
        at com.android.internal.policy.DecorView.dispatchKeyEvent(DecorView.java:351)
        at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:4714)
        at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4586)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4128)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4181)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4147)
        at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4274)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4155)
        at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4331)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4128)
        at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4181)
        at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4147)
        at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4155)
        at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4128)
        at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:6642)
        at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:6616)
        at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6577)
        at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:3911)
        at android.os.Handler.dispatchMessage(Handler.java:105)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6541)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
Process 7243 terminated.
android android-studio android-studio-3.0
1个回答
0
投票

在此行：int age = Integer.parseInt(userAge.getText().toString());之所以会收到NumberFormatException，是因为userAge.getText().toString()返回了一个空字符串（“”），该字符串无法解析为Integer，因为它不是数字。您的日志显示：

java.lang.NumberFormatException: For input string: ""
    at java.lang.Integer.parseInt(Integer.java:620)
    at java.lang.Integer.parseInt(Integer.java:643)
    at com.example.lifewirehours.MainActivity$3.afterTextChanged(MainActivity.java:98)
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