问题
I\'m new to Android, I\'ve followed the hello world tutorial through and have a basic idea of what\'s going on. I\'m particularly interested in the touch screen of my T-Mobile Pulse so just to get me started I want to be able to write the co-ordinates of a tocuh event on the screen, so say the user touched the co-ordinate 5,2 - a textview on the screen would display that.
At present I have a simple program that just loads an xml file which contains the textview I intend to write the co-ordinates in.
Thank you in advance, I did Google for help and searched stackoverflow but everything I found either went way over my head or wasn\'t suitable for this. Cheers.
回答1:
You can use this function : http://developer.android.com/reference/android/view/View.html#setOnTouchListener(android.view.View.OnTouchListener)
You will probably put it in your onCreate method roughly this way (tested this time) :
Activity onCreate code
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final TextView textView = (TextView)findViewById(R.id.textView);
// this is the view on which you will listen for touch events
final View touchView = findViewById(R.id.touchView);
touchView.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
textView.setText("Touch coordinates : " +
String.valueOf(event.getX()) + "x" + String.valueOf(event.getY()));
return true;
}
});
}
layout code
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:id="@+id/touchView"
android:background="#f00"
android:layout_weight="1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/textView"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Hello World, TestActivity"
/>
</LinearLayout>
Edit: I tried my code and indeed there were a few errors. Anyway, with the layout I give you here it works on my emulator. Can you provide maybe more code/context so I can see what's wrong?
回答2:
It sounds like you want to get touch events from the whole area of your layout for this particular test. Try attaching the touch listener to your parent view rather than a separate target view.
This isn't a very common approach. In most cases you will want to listen for touch events in a specific child view and if you have other views in your layout that handle touch events (such as a button) they'll take priority over a parent view. See http://developer.android.com/guide/topics/ui/ui-events.html for more info about handling UI events.
Layout (touch_viewer.xml):
<?xml version="1.0" encoding="utf-8" ?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:id="@+id/parent" >
<TextView android:id="@+id/text"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Hello, World!" />
</LinearLayout>
And in your activity:
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.touch_viewer);
final LinearLayout parent = (LinearLayout) findViewById(R.id.parent);
final TextView text = (TextView) findViewById(R.id.text);
parent.setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View v, MotionEvent ev) {
text.setText("Touch at " + ev.getX() + ", " + ev.getY());
return true;
}
});
}
回答3:
The following works using a touch screen on the jetboy sample android app. Joes code worked with one tweak to make it shine the background thru. The only line I added was
android:background="#0000"
android:layout_height="fill_parent"
android:layout_height="fill_parent"
Thanks Joe (above).
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final TextView textView = (TextView)findViewById(R.id.textView);
// this is the view on which you will listen for touch events
final View touchView = findViewById(R.id.touchView);
touchView.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
textView.setText("Touch coordinates : " +
String.valueOf(event.getX()) + "x" + String.valueOf(event.getY()));
return true;
}
});
}
layout code
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<com.android.samples.jetboy.JetBoyView android:id="@+id/JetBoyView"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
<TextView
android:id="@+id/touchView"
android:background="#0000"
android:layout_weight="1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
<TextView
android:id="@+id/textView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:text="Hello World, TestActivity"
/>
</FrameLayout>
回答4:
The corrected version without the errors:
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final TextView textView = (TextView) findViewById(R.id.textView);
// this is the view on which you will listen for touch events
final View touchView = findViewById(R.id.touchView);
touchView.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
textView.setText("Touch coordinates : "
+ String.valueOf(event.getX()) + "x"
+ String.valueOf(event.getY()));
return true;
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
来源：https://stackoverflow.com/questions/2939332/get-the-co-ordinates-of-a-touch-event-on-android