目标=把helloworld的文字变成可以缩放的,并可以移动文字块[scrollable]。
测试=需要能实体手机,虚拟机似乎不能进行触摸缩放测试。
版本=android 2.3.3,target=android-10
效果图
关键点
=============main.xml
<TextView android:id="@+id/text"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:scrollbars = "vertical"
android:text="@string/hello" />
显示纵向滚动条。
=============A1Activity.java
tvPosSave.set(xt, yt);
关键文件代码
=============main.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" >
<TextView android:id="@+id/text"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:scrollbars = "vertical"
android:text="@string/hello" />
</LinearLayout>
=============A1Activity.java
package com.ex.a1205;
import android.app.Activity;
import android.graphics.Point;
import android.graphics.PointF;
import android.os.Bundle;
import android.util.FloatMath;
import android.util.Log;
import android.util.TypedValue;
import android.view.Display;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.view.View.OnTouchListener;
import android.widget.TextView;
public class A1Activity extends Activity implements OnTouchListener {
enum Mode {
NONE, DRAG, ZOOM
}
Mode mode = Mode.NONE;
static final int MIN_FONT_SIZE = 20;
static final int MAX_FONT_SIZE = 120;
PointF start = new PointF();
Point tvPos0 = new Point();
Point tvPos1 = new Point();
Point tvPosSave = new Point();
float oldDist = 1f;
int scrWidth;
int scrHeight;
TextView textView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
textView = (TextView) findViewById(R.id.text);
loadDoc();
textView.setOnTouchListener(this);
Display display = ((WindowManager) getSystemService(WINDOW_SERVICE))
.getDefaultDisplay();
scrWidth = display.getWidth();
scrHeight = display.getHeight();
}
private void loadDoc() {
StringBuilder sb = new StringBuilder();
for (int i = 0; i <= 30; i++) {
sb.append("Line: ").append(i).append("\n");
}
textView.setText(sb.toString());
}
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
start.set(event.getX(), event.getY());
tvPos0.set((int) event.getX(), (int) event.getY());
mode = Mode.DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
if (oldDist > 10f) {
mode = Mode.ZOOM;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mode = Mode.NONE;
tvPos1.set(tvPosSave.x, tvPosSave.y);
break;
case MotionEvent.ACTION_MOVE:
if (mode == Mode.DRAG) {
doScroll(event);
} else if (mode == Mode.ZOOM) {
doZoom(event);
}
break;
}
return true;
}
private void doScroll(MotionEvent event) {
int xe = (int) event.getX();
int ye = (int) event.getY();
int txtHeight = textView.getLineHeight() * (textView.getLineCount() - 2);
int xt = tvPos1.x + tvPos0.x - xe;
int yt = tvPos1.y + tvPos0.y - ye;
if (xt < -textView.getRight()) {
xt = -textView.getRight() + 20;
} else if (xt > scrWidth) {
xt = scrWidth - 20;
}
if (yt < -textView.getBottom()) {
yt = -textView.getBottom() + textView.getLineHeight();
} else if (yt > txtHeight) {
yt = txtHeight;
}
textView.scrollTo(xt, yt);
tvPosSave.set(xt, yt);
// log("to(", xt, ",", yt, ")"
// , " tHt=", txtHeight
// );
}
void log(Object... objs) {
StringBuilder sb = new StringBuilder();
for (Object obj : objs) {
sb.append(obj);
}
Log.d(A1Activity.class.getSimpleName(), sb.toString());
}
private void doZoom(MotionEvent event) {
float newDist = spacing(event);
if (newDist > 10f) {
float scale = newDist / oldDist;
if (scale > 1) {
scale = 1.1f;
} else if (scale < 1) {
scale = 0.95f;
}
float currSize = textView.getTextSize() * scale;
if ((currSize < MAX_FONT_SIZE && currSize > MIN_FONT_SIZE)
|| (currSize >= MAX_FONT_SIZE && scale < 1)
|| (currSize <= MIN_FONT_SIZE && scale > 1)) {
textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, currSize);
}
}
}
/** Determine the space between the first two fingers */
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return FloatMath.sqrt(x * x + y * y);
}
}
好树
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