1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
package de.timfreiheit.mathjax.android;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Build;
import android.os.Handler;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.FrameLayout;
/**
* Containerview for an WebView which renders LaTex using MathJax
* https://github.com/mathjax/MathJax
* Created by timfreiheit on 26.05.15.
*/
public class MathJaxView extends FrameLayout {
private static final String HTML_LOCATION = "file:///android_asset/MathJaxAndroid/mathjax_android.html";
private final Handler handler = new Handler();
private final Context context;
protected MathJaxJavaScriptBridge mBridge;
private String inputText = null;
private WebView mWebView;
/**
* laTex can only be rendered when WebView is already loaded
*/
private boolean webViewLoaded = false;
private OnMathJaxRenderListener onMathJaxRenderListener;
public MathJaxView(Context context) {
super(context);
this.context = context;
init(context, null, null);
}
public MathJaxView(Context context, MathJaxConfig config) {
super(context);
this.context = context;
init(context, null, config);
}
public MathJaxView(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
init(context, attrs, null);
}
public MathJaxView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
this.context = context;
init(context, attrs, null);
}
public void setColor(String color) {
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
@Override
public void run() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
}
}
}, 500); // 5000ms delay
}
public void forceDark() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
mWebView.getSettings().setForceDark(WebSettings.FORCE_DARK_ON);
}
}
public void setRenderListener(OnMathJaxRenderListener onMathJaxRenderListener) {
this.onMathJaxRenderListener = onMathJaxRenderListener;
}
@SuppressLint({"SetJavaScriptEnabled", "AddJavascriptInterface"})
private void init(Context context, AttributeSet attrSet, MathJaxConfig config) {
mWebView = new WebView(context);
int gravity = Gravity.START;
boolean verticalScrollbarsEnabled = false;
boolean horizontalScrollbarsEnabled = true;
String textColor = config != null ? config.getTextColor() : null;
if (attrSet != null) {
TypedArray attrs = context.obtainStyledAttributes(attrSet, R.styleable.MathJaxView);
gravity = attrs.getInteger(R.styleable.MathJaxView_android_gravity, Gravity.START);
verticalScrollbarsEnabled = attrs.getBoolean(R.styleable.MathJaxView_verticalScrollbarsEnabled, false);
horizontalScrollbarsEnabled = attrs.getBoolean(R.styleable.MathJaxView_horizontalScrollbarsEnabled, true);
textColor = attrs.getString(R.styleable.MathJaxView_textColor);
config = new MathJaxConfig(attrs);
attrs.recycle();
}
if (config == null) {
config = new MathJaxConfig();
}
addView(
mWebView,
new LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT,
gravity
)
);
// callback when WebView is loading completed
webViewLoaded = false;
String finalTextColor = textColor;
mWebView.setWebViewClient(new WebViewClient() {
@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT && finalTextColor != null) {
view.evaluateJavascript("document.body.style.color=\"" + finalTextColor + "\";", null);
}
if (webViewLoaded) {
// WebView was already finished
// do not load content again
return;
}
webViewLoaded = true;
if (!TextUtils.isEmpty(inputText)) {
setInputText(inputText);
}
}
});
mBridge = new MathJaxJavaScriptBridge(this);
mWebView.addJavascriptInterface(mBridge, "Bridge");
mWebView.addJavascriptInterface(config, "BridgeConfig");
// be careful, we do not need internet access
mWebView.getSettings().setBlockNetworkLoads(true);
mWebView.getSettings().setJavaScriptEnabled(true);
mWebView.loadUrl(HTML_LOCATION);
mWebView.setVerticalScrollBarEnabled(verticalScrollbarsEnabled);
mWebView.setHorizontalScrollBarEnabled(horizontalScrollbarsEnabled);
mWebView.setBackgroundColor(0);
}
/**
* called when webView is ready with rendering LaTex
*/
protected void rendered() {
handler.postDelayed(new Runnable() {
@Override
public void run() {
mWebView.setVisibility(View.VISIBLE);
if (onMathJaxRenderListener != null)
onMathJaxRenderListener.onRendered();
}
}, 100);
}
/**
* @return the current laTex-String
* null if not set
*/
public String getInputText() {
return inputText;
}
/**
* change the displayed LaTex
*
* @param inputText formatted string
*/
public void setInputText(String inputText) {
this.inputText = inputText;
//wait for WebView to finish loading
if (!webViewLoaded) {
return;
}
String laTexString;
if (inputText != null) {
laTexString = doubleEscapeTeX(inputText);
} else {
laTexString = "";
}
mWebView.setVisibility(View.INVISIBLE);
String javascriptCommand = "javascript:changeLatexText(\"" + laTexString + "\")";
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
mWebView.evaluateJavascript(javascriptCommand, null);
} else {
mWebView.loadUrl(javascriptCommand);
}
}
private String doubleEscapeTeX(String s) {
String t = "";
for (int i = 0; i < s.length(); i++) {
if (s.charAt(i) == '\'') t += '\\';
if (s.charAt(i) == '\\') t += "\\";
if (s.charAt(i) != '\n') t += s.charAt(i);
}
return t;
}
public interface OnMathJaxRenderListener {
void onRendered();
}
}
|
