Question

Im trying to make my first application to calcaulate physical activities for me. At first, ive tried to make simple chronometer with start and stop button.

XML:

<Core:CallMethodAction MethodName="GotoDetailsPage" TargetObject="{Binding ElementName=ViewModel}" />

and of course activity.java

<LinearLayout
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight="0">

    <ImageView
        android:layout_width="107dp"
        android:layout_height="93dp"
        android:id="@+id/Fit_logo"
        android:src="@drawable/fitapp_gray"
        android:layout_marginLeft="30dp" />

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="30dp">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceSmall"
            android:text="Current time"
            android:id="@+id/CurrentTime"
            android:layout_gravity="center_horizontal" />

        <TextClock
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/time"
            android:layout_gravity="center_horizontal"
            android:textSize="25sp"
            android:textColor="#ffffff" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="Degree"
            android:id="@+id/degree"
            android:layout_gravity="center_horizontal" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:text="City"
            android:id="@+id/city"
            android:layout_gravity="center_horizontal" />
    </LinearLayout>

</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:color/white"
    android:orientation="vertical"
    android:layout_weight="1"
    android:layout_marginBottom="100dp"
    android:layout_gravity="center">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:text="Duration"
        android:id="@+id/duration"
        android:gravity="center_horizontal"
        android:layout_marginTop="10dp" />

    <Chronometer
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/chronometer"
        android:layout_gravity="center_horizontal"
        android:textSize="30sp" />

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="center">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceSmall"
            android:text="Calories"
            android:id="@+id/calories"
            android:layout_weight="1"
            android:gravity="center"
            android:layout_marginTop="50dp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceSmall"
            android:text="Steps"
            android:id="@+id/steps"
            android:layout_weight="1"
            android:gravity="center"
            android:layout_marginTop="50dp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceSmall"
            android:text="Distance"
            android:id="@+id/distance"
            android:layout_weight="1"
            android:gravity="center"
            android:layout_marginTop="50dp" />
    </LinearLayout>

</LinearLayout>

<LinearLayout
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical|center|center_horizontal">

    <ImageButton
        android:layout_width="100dip"
        android:layout_height="100dip"
        android:id="@+id/btnStart"
        android:background="@drawable/startbutton"
        android:clickable="true"
        android:layout_marginBottom="70dp"
        android:layout_gravity="bottom|center_horizontal" />

    <Space
        android:layout_width="100dp"
        android:layout_height="wrap_content" />

    <ImageButton
        android:layout_width="100dip"
        android:layout_height="100dip"
        android:id="@+id/btnStop"
        android:background="@drawable/stopbutton"
        android:clickable="true"
        android:layout_marginBottom="70dp"
        android:layout_gravity="bottom|center_horizontal" />
</LinearLayout>

</LinearLayout>

but everytime I try to run the app it force closes itself just before start.

final Chronometer chronometer =  (Chronometer)  findViewById(R.id.chronometer);
final ImageButton start = (ImageButton) findViewById(R.id.btnStart);
final ImageButton stop = (ImageButton) findViewById(R.id.btnStop);


start.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        chronometer.start();
        Toast.makeText(Activity_cal.this, "Chronometer Started", Toast.LENGTH_SHORT).show();
    }
});
 stop.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
    chronometer.stop();
    }
});

Fatal error is for Start button. Could anybody kick me in right direction what else to do? Thanks

Answer 1

好的，我已经制作了包含所有参数的全新项目。制作新的工具方法，现在可以使用了。感谢您的帮助，我感谢所有答案;）

Answer 2

我认为问题在于您是否正在尝试从支持库转换为小部件。更改导入，使两者兼容。

Answer 3

看来你正在尝试以错误的方式投射AppCompatButton Button ImageButton

投射错误意味着你尝试识别不同类型的属性

Ex：在您的xml中

 <ImageButton
        android:layout_width="100dip"
        android:layout_height="100dip"
        android:id="@+id/btnStart"
        android:background="@drawable/startbutton"
        android:clickable="true"
        android:layout_marginBottom="70dp"
        android:layout_gravity="bottom|center_horizontal" />

在java中

              //  here is casting
Button mStartButton = (Button) findViewById(R.id.btnStart);

问题是在xml中你将它定义为ImageButton但在java中却将其定义为Button因此它崩溃并告诉你不能转换为不同的类型

Unable to start activity. chronometer start button

3 个答案: